THE  UNIVERSITY 

OF  ILLINOIS 

LIBRARY 


<S_o-ip.    >O 

AGRICULTURAL 
IJBRARV 


UNIVERSITY  OF  ILLINOIS 

Agricultural  Experiment  Station 


BULLETIN  No.  200 


WITH   SPECIAL  REFERENCE 


By  H.  S.  GRINDLEY,  W.  J.  CARMICHAEL,  AND  C.  I.  NEWLIN 


URBANA,  ILLINOIS,  MAY,  1917 


CONTENTS  OF  BULLETIN  No.  200 

Page 

1.  OBJECTS  OF  EXPERIMENTS  55 

FIRST  SERIES  OF  EXPERIMENTS,  1913-1914 

2.  PLAN 55 

3.  CHEMICAL  COMPOSITION  OF  FEEDS  AND  FECES;  AND  WEIGHTS  OF  PIGS, 

FEEDS,  WATER,  FECES,  AND  URINE , 56 

4.  COEFFICIENTS  OF  DIGESTIBILITY  OF  THE  NUTRIENTS  OF  THE  RATIONS 

(a)  Wheat  flour  middlings 61 

(b)  Ground  corn 62 

(c)  Wheat  flour  middlings  and  ground  corn  (1  to  1) 62 

(d)  Tankage  and  ground  corn  (1  to  7.5) 63 

5.  THE  INFLUENCE  OF  ONE  FEED  UPON  THE  DIGESTIBILITY  OF  THE  NUTRIENTS 

OF  ANOTHER  FEED 65 

6.  COEFFICIENTS  OF  DIGESTIBILITY  OF  MIDDLINGS,  DIRECTLY  AND  INDIRECTLY 

DETERMINED 67 

7.  COEFFICIENTS  OF  DIGESTIBILITY  OF  GROUND  CORN,  DIRECTLY  AND  INDI- 

RECTLY DETERMINED 68 

8.  COEFFICIENTS  OF  DIGESTIBILITY  OF  A  RATION  OF  MIDDLINGS  AND  GROUND 

CORN   (1  TO  1),  DIRECTLY  AND  INDIRECTLY  DETERMINED 69 

9.  INDIVIDUALITY  OF  PIGS  AS  TO  THE  THORONESS  WITH  WHICH  THEY  DIGEST 

THEIR  FEED 70 

10.  SUMMARY  OF  THE  COEFFICIENTS  OF  DIGESTIBILITY  OF  THE  NUTRIENTS 

SHOWING  THE  INDIVIDUALITY  OF  PIGS  AS  TO  THE  THORONESS  WITH 
WHICH  THEY  DIGESTED  THEIR  FEED  IN  THE  FIRST  SERIES  OF  EXPERI- 
MENTS    72 

SECOND  SERIES  OF  EXPERIMENTS,  1914-1915 

11.  PLAN 72 

12.  CHEMICAL  COMPOSITION  OF  FEEDS  AND  FECES;  AND  WEIGHTS  OF  PIGS, 

FEEDS,  WATER,  FECES,  AND  URINE 73 

13.  COEFFICIENTS  OF  DIGESTIBILITY  OF  THE  NUTRIENTS  OF  THE  RATIONS 

(a)  Ground  barley 75 

(b)  Ground  corn 77 

(c )  Ground  barley  and  ground  corn  (1  to  1) 77 

(d)  Tankage  and  ground  com   (1  to  7.5) 80 

14.  THE  INFLUENCE  OF  ONE  FEED  UPON  THE  DIGESTIBILITY  OF  THE  NUTRIENTS 

OF  ANOTHER  FEED 80 

15.  COEFFICIENTS  OF  DIGESTIBILITY  OF  GROUND  BARLEY,  DIRECTLY  AND  INDI- 

RECTLY DETERMINED 81 

16.  COEFFICIENTS  OF  DIGESTIBILITY  OF  GROUND  CORN,  DIRECTLY   AND  INDI- 

RECTLY DETERMINED 82 

17.  COEFFICIENTS  OF  DIGESTIBILITY  OF  A  RATION  OF  GROUND  BARLEY  AND 

GROUND  CORN  (1  TO  1),  DIRECTLY  AND  INDIRECTLY  DETERMINED.  ...     83 

18.  INDIVIDUALITY  OF  PIGS  AS  TO  THE  THORONESS  WITH  WHICH  THEY  DIGEST 

THEIR  FEED   85 

19.  SUMMARY  OF  THE  COEFFICIENTS  OF  DIGESTIBILITY  OF  THE  NUTRIENTS 

SHOWING  THE  INDIVIDUALITY  OF  PIGS  AS  TO  THE  THORONESS  WITH 
WHICH  THEY  DIGESTED  THEIR  FEED  IN  THE  SECOND  SERIES  OF  EX- 
PERIMENTS.. 87 


20.  SUMMARY  OF  DATA  OF  BOTH  SERIES  OF  EXPERIMENTS 87 

21.  CONCLUSIONS..  89 


DIGESTION  EXPERIMENTS  WITH  PIGS 

WITH  SPECIAL  REFERENCE 

TO  THE  INFLUENCE  OF  ONE  FEED  UPON  ANOTHER,  AND 
TO  THE  INDIVIDUALITY  OF  PIGS 

BY  H.  S.  GRINDLEY,  CHIEF  IN  ANIMAL  NUTRITION, 

W.  J.  CARMICHAEL,  FIRST  ASSISTANT  IN  ANIMAL  HUSBANDRY,  AND 

C.  I.  NEWLIN,  FIRST  ASSISTANT  IN  ANIMAL  HUSBANDRY 

OBJECTS  OF  THE  EXPERIMENTS 

The  objects  of  the  experiments  reported  in  this  bulletin  were  as 
follows:  (a)  to  determine  the  influence  of  one  feed  upon  the  digesti- 
bility of  the  nutrients  of  another  feed;  (b)  to  study  the  individual- 
ity of  pigs  as  to  the  thoroness  with  which  they  digest  their  feed ;  and 
(c)  to  determine  the  coefficients  of  apparent  digestibility1  of  the  nutri- 
ents of  the  following  rations:  (1)  wheat  flour  middlings,  (2)  ground 
corn,  (3)  ground  barley,  (4)  wheat  flour  middlings  and  ground  corn 
in  the  ratio  of  1  to  1,  (5)  ground  barley  and  ground  corn  in  the 
ratio  of  1  to  1,  and  (6)  tankage  and  ground  corn  in  the  ratio  of  1  to 
7.5.  In  order  to  secure  experimental  data  that  would  answer  the 
questions  suggested  by  the  above  objects,  ground  corn,  wheat  flour 
middlings,  and  tankage  were  the  feeds  used  in  the  first  series  of  ex- 
periments; and  ground  corn,  ground  barley,  and  tankage  were  used 
in  the  second  series  of  experiments. 

FIRST  SERIES  OF  EXPERIMENTS,  1913-1914 
PLAN 

Four  cross-bred  Berkshire-Chester  White  barrows  a  little  over 
seven  months  old,  and  all  from  the  same  litter,  were  selected  for  this 
work  and  put  into  specially  constructed  pens.  These  pens  (Fig.  1) 
were  large  enough  to  allow  the  pigs  to  turn  around  conveniently,  and 
were  raised  some  three  feet  from  the  floor  to  enable  an  easy  collection 
of  the  urine.  They  were  provided  with  removable  galvanized-iron  feed 
troughs  (Fig.  2)  'and  with  hinged  doors,  thru  which  the  animals  were 

1Strietly  speaking,  the  coefficients  of  the  real  digestibility  of  the  nutrients  of 
feeds  cannot  as  yet  be  determined,  for  it  is  impossible  to  estimate  accurately  in 
the  feces,  either  the  metabolic  products  of  intestinal  action  or  the  products  resulting 
from  tissue  metabolism  that  are  excreted  thru  the  intestinal  walls  into  the  alimen- 
tary canal.  Therefore,  thruout  this  bulletin  the  coefficients  of  digestibility  represent 
the  coefficients  of  apparent  digestibility;  that  is,  merely  the  differences  between  the 
weights  of  the  nutrients  in  the  feeds  and  in  the  feces  expressed  in  percent  of  the 
former. 

55 


56  BULLETIN  No.  200  [May, 

driven  to  the  weighing  crate.  The  floor,  consisting  of  a  strong  wire 
screen,  fitted  tightly  over  a  galvanized-iron  hopper  leading  to  the  urine 
pail  (Fig.  3).  No  chemical  analyses  of  the  urines  were  made.  The 
f  eces,  collected  in  rubber-lined  canvas  bags  held  in  place  by  means  of  a 
specially  constructed  harness  (Fig.  4),  were  removed  each  day  and 
placed  in  friction-top  cans. 

Corn  and  wheat  flour  middlings  were  chosen  because  they  are  two 
of  the  most  common  and  practical  feeds  used  for  swine  in  the  corn 
belt.  No.  2  yellow  corn  was  used.  Digester  tankage  (meat  meal)  con- 
taining over  60  percent  of  protein  was  fed  in  two  periods  of  the  ex- 
periment. The  barrows  were  fed  twice  daily,  at  7  a.  m.  and  5  p.  m. 
The  different  rations  were  given  in  amounts  that  the  pigs  would  clean 
up  readily,  this  quantity  being  determined  during  a  period  of  several 
days'  duration  immediately  preceding  the  experiments  proper.  Each 
of  the  rations  was  mixed  with  a  definite  amount  of  water  (as  much  as 
the  pigs  would  take)  and  fed  as  a  moderately  thin  slop. 

The  first  ration  for  which  the  coefficients  of  digestibility  were  de- 
termined consisted  approximately  of  2.17  pounds  of  middlings  per 
100  pounds  live  weight;  the  second,  of  1.04  pounds  of  middlings  and 
1.04  pounds  of  ground  corn  per  100  pounds  live  weight;  the  third, 
of  2.06  pounds  of  ground  corn  per  100  pounds  live  weight ;  the  fourth 
of  1.84  pounds  of  middlings  per  100  pounds  live  weight;  and  the 
fifth,  of  1.74  pounds  of  ground  corn  and  0.23  pounds  of  tankage  per 
100  pounds  live  weight.  Each  of  these  rations  was  fed  for  two  ten- 
day  test  periods,  during  which  time  composite  samples  of  the  feeds 
and  feces  were  taken  for  chemical  analysis. 

Each  group  of  the  two  ten-day  test  periods  was  preceded  by  a  pre- 
liminary period  of  twenty-five  to  thirty-two  days'  duration.  During 
the  first  seven  to  ten  days  of  each  preliminary  period,  the  change  in 
the  kinds  of  feed  was  made ;  during  the  remainder  of  the  preliminary 
period,  the  pigs  were  fed  the  same  ration  in  the  same  amounts  per 
hundred  pounds  of  live  weight  that  they  were  to  be  fed  during  the 
two  test  periods  immediately  following.  During  the  last  ten  days  of 
each  preliminary  period,  the  pigs  were  in  their  pens,  fully  harnessed, 
in  order  that  they  might  have  sufficient  time  to  become  accustomed  to 
the  experimental  conditions  before  any  data  were  recorded. 

CHEMICAL  COMPOSITION  OF  FEEDS  AND  FECES  ;  AND  WEIGHTS  OF  PIGS, 
FEEDS,  WATER,  FECES,  AND  URINE 

The  chemical  composition  of  the  feeds  and  fresh  feces  are  given  in 
Tables  1  and  3,  respectively.  The  weights  of  the  pigs,  the  feeds,  the 
water,  the  feces,  and  the  urine  for  each  experimental  period  are  given 
in  Table  2. 

From  the  data  given  in  Table  2,  it  will  be  noted  that  the  weights 
of  the  feces  per  pound  of  feed  varied  markedly  depending  upon  the 


1917] 


DIGESTIBILITY  OF  MIXED  FEEDS  ;    INDIVIDUALITY  OF  PIGS 


57 


character  of  the  ration.  The  average  weights  of  the  fresh  feces  per 
pound  of  feed  were  as  follows:  In  Periods  1  and  2,  and  7  and  8,  in 
which  middlings  alone  were  fed,  1.13  and  0.99  pounds,  respectively; 
in  Periods  3  and  4,  in  which  middlings  and  ground  corn  in  the  ratio 
of  1  to  1  were  fed,  0.74  pounds ;  in  Periods  9  and  10,  in  which  tank- 
age and  ground  corn  in  the  ratio  of  1  to  7.5  were  fed,  0.39  pounds; 
and  in  Periods  5  and  6,  in  which  ground  corn  alone  was  fed,  0.355 
pounds. 

Examination  of  Table  3,  giving  the  composition  of  the  fresh  feces, 
and  of  Table  4,  showing  the  coefficients  of  digestibility  of  the  nutrients 
of  the  rations,  shows  that  the  above  differences  in  weights  of  the  feces 
per  pound  of  feed  due  to  the  character  of  the  ration  consumed,  can 
be  traced,  in  large  part  at  least,  to  the  variations  in  the  water  content 
of  the  feces  and  to  the  variations  in  the  coefficients  of  digestibility  of 
the  dry  substance  of  the  rations.  Thus,  the  average  water  content  of 
the  feces  for  the  several  periods  wa"s  as  follows:  Periods  1  and  2, 
and  7  and  8,  in  which  middlings  alone  were  fed,  79.83  and  76.51  per- 
cent, respectively;  Periods  3  and  4,  in  which  middlings  and  ground 
corn  in  the  ratio  of  1  to  1  were  fed,  75.15  percent ;  Periods  9  and  10, 
in  which  tankage  and  ground  corn  in  the  ratio  of  1  to  7.5  were  fed, 
69.83 ;  and  Periods  5  and  6,  in  which  ground  corn  alone  was  fed,  70.28 
percent. 

The  average  coefficients  of  digestibility  of  the  dry  substance  of  the 
rations  for  the  several  periods  were  as  follows :  Periods  1  and  2,  and  7 
and  8,  in  which  middlings  alone  were  fed,  74.7  and  74.2,  respectively ; 
Periods  3  and  4,  in  which  middlings  and  ground  corn  in  the  ratio  of 
1  to  1  were  fed,  79.1 ;  Periods  9  and  10,  in  which  tankage  and  ground 
corn  in  the  ratio  of  1  to  7.5  were  fed,  86.8 ;  and  Periods  5  and  6.  in 
which  ground  corn  alone  was  fed,  87.9. 

TABLE  1. — CHEMICAL  COMPOSITION  OF  THE  FEEDS 
(Results  expressed  in  percent  of  the  fresh  substance) 


Nitro- 

Non- 

Kind  of  feed 

Used 
in 
periods 

Dry 

sub- 
stance 

gen- 
free 
ex- 
tract 

Crude 
fiber 

Crude 
pro- 
tein 

Ether 
ex- 
tract 

Crude 
ash 

pro- 
tein 
nitro- 
gen 

Total 
nitro- 
gen 

Ground  corn  .... 
Ground  corn  .... 
Average  

3,  4,  5,  6 
9,10 

86.38 
88.47 
87.42 

71.74 
71.63 
71.68 

1.95 
2.31 
2.13 

8.45 
9.30 
8.87 

2.95 
3.95 
3.45 

1.29 
1.28 
1.28 

0.177 
'  0.156 
0.166 

1.352 
1.489 
1.420 

Wheat  flour 

middlings.  .  .  . 
Wheat  flour 

1,2 

89.64 

54.98 

5.92 

18.33 

5.85 

4.58 

0.615 

2.932 

middlings.  .  .  . 
Average  

3,  4,  7,  8 

89.95 
89.79 

54.98 
54.98 

6.01 
5.97 

18.06 
18.19 

6.05 
5.95 

4.75 
4.66 

0.631 
0.623 

2.890 
2.911 

Tankasre.  . 

9.10 

92.06 

3.96 

3.10 

62.58 

7.56 

14:84 

3.382 

10.013 

58 


BULLETIN  No.  200 


[May, 


TABLE  2. — WEIGHTS  OF  PIGS,  FEEDS,  WATER,  FECES,  AND  URINE 
(Eesults  expressed  in  pounds) 


Feeds  consumed 

Feces 

Per 

Pig 

Live 
weight 

Mid- 
dlings 

Ground 
corn 

Total 

day 
per 
100  Ibs. 

Water 

Total 
feces 

per 
Ib.of 
feed 

Total 
urine1 

live 

weight 

First  Test  Period.     December  18  to  27,  1913.     Ten  days.     Middlings 


113 

181.8 

39.60 

39.60 

2.18 

158.40 

44.67 

1.13 

213 

181.5 

39.60 

39.60 

2.18 

158.40 

48.31 

1.22 

313 

149.4 

33.00 

33.00 

2.21 

132.00 

37.50 

1.14 

413 

149.3 

33.00 

33.00 

2.21 

132.00 

35.23 

1.07 

Average 

165.5 

36.30 

36.30 

2.20 

145.20 

41.43 

1.14 

Second  Test  Period.    December  28,  1913  to  January  6,  1914.    Ten  days.    Middlings 


113 

186.5 

39.60 

39.60 

2.12 

15840 

45.37 

1  15 

213 

186.7 

39.60 

39.60 

2.12 

158.40 

46.39 

1.17 

313 

153.1 

33.00 

33:00 

2.16 

132.00 

35.95 

1.09 

413 

154.5 

33.00 

33:00 

2.14 

132.00 

35.36 

1.07 

Average 

170.2 

36.30 

36.30 

2.14 

145.20 

40.77 

1.12 

Third  Test  Period.    January  24  to  February  2,  1914.     Ten  days.    Middlings  and 

ground  corn  (1  to  1) 


113 
213 
313 
413 

207.0 
207.6 
174.3 
172.4 

22,0'0 
22.00 
18.00 
18.00 

22.00 
22.00 
18.00 
18.00 

44.00 
44.00- 
36.00 
36:00 

2.13 
2.12 
2.07 
2.09 

176.00 
176.00 
144.00 
144.0,0 

31.99 
32.33 
25.72 
26.18 

0.73 
0.73 
0.71 
•0.73 

120.042 
136.38 
113.05 
114.32 

Average 

190.3 

20.00 

20.00 

40.00 

2.10 

160.00 

29.05 

0.72 

120.95 

Fourth  Test  Period.    February  3  to  12,  1914.     Ten  days.     Middlings  and  ground 
corn   (1  to  1) 

113 
213 
313 
413 

213.2 
212.0 
177.0 
175.7 

22.00 
22.00 
18.00 
18.00 

22.00 
22.00 
IS.0'0 
18.00 

44.00 
44.00 
36.00 
36.00 

2.06 
2.08 
2.03 
2.05 

176:00 
176.00 
144.00 
144.00 

33.84 
33.63 
26.51 
27.54 

0,77 
0.76 
0.74 
0.76 

134.42 
136.80 
-104.86' 
90.84' 

Average 

194.5 

20.00 

20.00 

40.00 

2.06 

160.00 

30.38 

0.76 

116.73 

Fifth  Test  Period.     March  7  to  17,  1914.     Ten  days.     Ground  corn 

113 
213 
313 
413 

228.0 
231.4 
193.3 
192.5 

48.00 
48:00 
40.00 
40.00 

48.00 
48.00 
40.00 
40.00 

2.11 

2.07 
2.07 
2.08 

180.90 
164.70 
157.10 
120.00 

17.12 
18.85 
13.62 
13.58 

0.36 
0.39 
0.34 
0.34 

153.95 
143.64 
136.69 
103.71 

Average 

211.3 

44.00 

44.00 

2.08 

155.67 

15.79 

0.36 

134.50 

1Weight  of  urine  for  first  and  second  periods  not  recorded. 
2Weight  for  9  days  only. 
'Weight  for  8  days  only. 


1917] 


DIGESTIBILITY  OP  MIXKD  FEEDS;    INDIVIDUALITY  OF  PIGS 


59 


TABLE  2. — Concluded 


Pig 

Live 
weight 

Feeds  consumed 

Water 

Total 
feces 

Feces 
per 
Ib.of 
feed 

Total 
urine 

Mid- 
dlings 

Ground 
corn 

Total 

Per 
day 
per 

100  Ibs. 
live 
weight 

Sixth  Test  Period.    March  18  to  27,  1914.     Ten  days.    Ground  corn 


113 

234.2 

48.00 

48.00 

2.05 

160.40 

16.80 

0.35 

137.19 

213 

236.0 

48.00 

48.00 

2.03 

181.80 

17.97 

0.37 

155.07 

313 

197.3 

40,00 

40.00 

2,03 

160.00 

13:07 

0.33 

140.35 

413 

196.8 

40.00 

40.00 

2.03 

125.50 

14.00 

0.35 

111.10 

Average 

216.1 

44.00 

44.00 

2.04 

156.92 

15.46 

0.35 

135.93 

Seventh  Test  Period.    April  26  to  May  5,  1914.    Ten  days.  Middlings 


113 

283.0 

52.00 

52.00 

1.84 

208.00 

57.00 

1.10 

150.94 

213 

283.2 

52.00 

52:00 

1.84 

208.00 

52.66 

1.01 

155.93 

313 

248.3 

46.00 

46,00 

1.85 

184.00 

45.57 

0.99 

140.66 

413 

240.8 

46.00 

46.00 

1.91 

184.00 

46.89 

1.02 

142.76 

Averasre 

263.8 

49.00 

49.00 

1.86 

196.00 

50.53 

1.03 

147.57 

Eighth  Test  Period.    May  6  to  15,  1914.    Ten  days.    Middlings 


113 
213 
313 
413 

292.3 
290.7 
255.3 
247..7 

52.00- 
52,00 
46.00 
46.00 

52.00 
52.00 
46.00 
46.0'0 

1.78 
1.79 
1.80 
1.86 

208.0 
208.0 
184.0 
184.0 

51.64 
50.14 
44.67 
40.94 

0.99 
0.96 
0.97 
0.89 

155.32 
155.81 
142.21 
143.65 

Average 

271.5 

49.00 



49.00 

1.81 

196.0 

46.85 

0.95 

149.25 

Ninth  Test  Period.    June  5  to  14,  1914.    Ten  days.    Tankage  and  ground  corn 
(1  to  7.5) 

113 
213 
313 
413 

332.0 
332.7 
292.4 
283.4 

8.00 
8.00 
6.60 
6.60 

60.00 
60.00 
50.00 
50.00 

68.00 
68.00 
56.60 
56.60 

2.05 
2.04 
1.94 
2.00 

210.50 
201.00 
191.20 
176.60 

24.57 
29.72 
21.10 
23.59 

0.36 
0.44 
0.37 
0.42 

100.62 
102.91 
110.28 
113.20 

Average 

310.1 

7.30 

55.00 

62.30 

2.01 

194.82 

24.74 

0.40 

106.75 

Tenth  Test  Period.     June  15  to  24,  1914.     Ten  days.     Tankage  and  ground  corn 
(1  to  7.5) 

113 
213 
313 
413 

347.4 
346.4 
302.6 
297.1 

8.00 
8.00 
6.60 
6.60 

60.00 
60.00 
50.00 
50.00 

68.00 
68.00 
56.60 
56.60 

1.96 
1.96 
1.87 
1.91 

205.10 
193.50 
191.80 
157.70 

26.04 
29.40 
19.59 
21.43 

0.38 
0.43 
0.35 
0.38 

126.70 
119.02' 
127.79 
98.03 

Average 

323.4 

7.30 

55.00 

62.30 

1.93 

187.02 

24.11 

0.38 

117.88 

60 


BULLETIN  No.  200 


[May, 


TABLE  3. — CHEMICAL  COMPOSITION  OF  THE  FECES 
(Eesults  expressed  in  percent  of  fresh  substance) 


Nitro- 

Non- 

Nitro- 

Dry 

gen- 

Crude 

Ether 

pro- 

Total 

gen  in- 

Pig 

sub- 

free 

Crude 

pro- 

ex- 

Crude 

tein 

nitro- 

soluble 

stance 

ex- 

fiber 

tein 

tract 

ash 

nitro- 

gen 

in  acid 

tract 

gen 

pepsin 

First  Test  Period.     December  18  to  27,  1913.     Ten  days.     Middlings 


113 
213 
313 
413 

19.64 
19.34 

18.88 
21.08 

8.05 
7.99 

7.84 
8.89 

4.12 
3.87 
3.97 
4.14 

3.47 
3.39 
3.14 
3.79 

0.93 
1.07 
0.88 
1.06 

3.02 
3.03 
3.06 
3.20 

0.161 
0.157 
0.158 
0.163 

0.555 
0.542 
0.502 
0.607 

0.205 
0.213 
0.210 
0.198 

Average 

19.74 

8.19 

4.02 

3.45 

0.98 

3.08 

0.160 

0.551 

0.206 

Second    Test    Period.      December    28,    1913    to    January    6,    1914.      Ten    days. 
Middlings 

113 
213 
313 
413 

19.34 
19.78 
21.07 
22.23 

8.35 
8.61 
9.46 
10.39 

4.02 
4.07 
4.63 
3.64 

3.19 
3.20 
2.94 
3.83 

0.66 
0.88 
0.76 
1.11 

3.13 
3.03 
3.27 
3.26 

0.189 
0.172 
0.140 
0.140 

0.510 
0.511 
0.471 
0.590 

0.205 
0.194 
0.208 
0.187 

Average 

20.60 

9.20 

4.09 

3.29 

0.85 

3.17 

0.160 

0.520 

0.198 

Third  Test  Period.    January  24  to  February  2,  1914.    Ten  days.   Middlings  and 
ground  corn  (1  to  1) 

113 
213 
313 
413 

25.38 
25.39 
24.28 
24.71 

12.62 
12.62 
11.77 
11.62 

4.48 
4.27 
4.96 

4.82 

3.97 
4.24 
3.42 
4.55 

1.34 
1.31 
0.80 
0.73 

2.97 
2.95 
3.34 
3.01 

0.129 
0.129 
0.098 
0.130 

0.635 
0.678 
0.546 
0.727 

0.228 
0.201 
0.293 
0.260 

Average 

24.94 

12.16 

4.63 

4.04 

1.04 

3.07 

0.121 

0.646 

0.245 

Fourth  Test  Period.    February  3  to  12,  1914!    Ten  days.    Middlings  and  ground 

corn  (1  to  1) 


113 

24.61 

11.25 

5.23 

3.78 

1.29 

3.06 

0.129 

0.605 

0.224 

213 

24.28 

12.05 

4.35 

4.10 

0.93 

2.85 

0.152 

0.655 

0.181 

313 

25.18 

12.00 

5.31 

3.93 

0.79 

3.14 

0.207 

0.628 

0.183 

413 

25.01 

12.08 

4.76 

4.51 

0.87 

2.85 

0.177 

0.721 

0.257 

Average 

24.77 

11.85 

4.91 

4.08 

0.97 

2.97 

0.166 

0.652 

0.211 

Fifth  Test  Period.    March  7  to  17,  1914.    Ten  days.     Ground  corn 


113 

27.41 

13.90 

3.98 

5.49 

1.39 

2.66 

0.180 

0.878 

0.206 

213 

29.43 

13.77 

3.91 

6.08 

3.21 

2.46 

0.172 

0.973 

0.183 

313 

29.83 

15.92 

3.43 

5.90 

1.80 

2.76 

0.177 

0.944 

0.219 

413 

29.25 

13.65 

4.03 

5.84 

3.18 

2.56 

0.170 

0.935 

0.210 

Average 

28.98 

14.31 

3.84 

5.83 

2.39 

2.61 

0.175 

0.932 

0.204 

1917 J  DIGESTIBILITY  OF  MIXED  FEEDS;    INDIVIDUALITY  OF  Pies 

TABLE  3. — Concluded 


61 


Nitro- 

Non- 

Nitro- 

Dry 

gen- 

Crude 

Ether 

pro- 

Total 

gen  in- 

Pig 

sub- 

free 

Crude 

pro- 

ex- 

Crude 

tein 

nitro- 

soluble 

stance 

ex- 

fiber 

tein 

tract 

ash 

nitro- 

gen 

in  acid 

tract 

gen 

pepsin 

Sixth  Test  Period.    March  18  to  27,  1914.    Ten  Days.    Ground  corn 


113 
213 
313 
413 

29.71 
31.52 
29.41 
31.21 

16.08 
15.33 
14.49 
16.03 

3.67 
4.15 
3.41 
3.88 

5.53 
6.58 
6.12 
6.06 

1.49 
2.78 
2.51 
2.46 

2.94 
2.67 
2.87 
2.79 

0.257 
0.223 
0.238 
0.239 

0.884 
1.053 
0.979 
0.969 

0.216 
0.188 
0.234 
0.290 

Average 

30.46 

15.48 

3.78 

6.07 

2.31 

2.82 

0.239 

0.971 

0.232 

Seventh  Test  Period.    April  26  to  May  5,  1914.    Ten  days.    Middlings 

113 
213 
313 
413 

21.90 
23.79 
22.73 
24.58 

10.13 
11.66 
11.03 
11.63 

4.63 
4.40 
4.60 
5.00 

3.41 
3.76 
3.08 
3.85 

0.60 
0.68 
0.73 
0.83 

3.14 
3.29 
3.30 
3.27 

0.204 
0.241 
0.166 
0.199 

0.545 
0.602 
0.492 
0.617 

0.158 
0.174 
0.194 
0.209 

Average 

23.25 

11.11 

4.66 

3.52 

0.71 

3.25 

0.202 

0.564 

0.184 

Eighth  Test  Period.    May  6  to  15,  1914.    Ten  days.    Middlings 

113 
213 
313 
413 

22.29 
23.61 
23.68 
25.34 

9.96 
10.91 
10.73 
11.59 

4.96 
5.02 
4.97 
5.34 

3.52 
3.65 
3.27 
4.04 

0.43 
0.63 
0.73 
0.89 

3.41 
3.40 
3.58 
3.49 

0.201 
0.198 
0.146 
0.207 

0.563 
0.583 
0.523 
0.647 

0.206 
0.207 
0.196 
0.217 

Average 

23.73 

10.80 

5.07 

3.62 

0.67 

3.47 

0.188 

0.579 

0.206 

Ninth  Test  Period.    June  5  to  14,  1914.    Ten  days.    Tankage  and  ground  corn 

(1  to  7.5) 


113 

31.33 

13.12 

3.34 

9.46 

1.61 

3.80 

0.340 

1.514 

0.408 

213 

28.51 

11.51 

3.25 

9.59 

1.23 

2.93 

0.388 

1.535 

0.484 

313 

29.78 

11.52 

2.98 

10.40 

0.90 

3.99 

0.351 

1.664 

0.771 

413 

30.92 

13.08 

3.19 

9.73 

2.09 

2.82 

0.303 

1.557 

0.493 

Average 

30.14 

12.31 

3.19 

9.80 

1.46 

3.38 

0.346 

1.568 

0.539 

Tenth  Test  Period.    June  15  to  24,  1914.     Ten  days.     Tankage  and  ground  corn 

(1  to  7.5) 


113 

30.85 

12.92 

2.97 

9.38 

1.53 

4.05 

0.386 

1.501 

0.557 

213 

30.13 

12.53 

2.83 

9.68 

1.76 

3.33 

0.403 

1.548 

0.608 

313 

29.59 

11.13 

2.75 

10.32 

1.57 

3.83 

0.371 

1.652 

0.725 

413 

30.22 

12.05 

2.89 

10.17 

1.96 

3.14 

0.369 

1.628 

0.579 

Average 

30.20 

12.16 

2.86 

9.89 

1.70 

3.59 

0.382 

1.582 

0.617 

COEFFICIENTS  OF.  DIGESTIBILITY  OF  THE  NUTRIENTS  OF  THE  RATIONS 

The  coefficients  of  the  digestibility  of  the  nutrients  of  the  rations 
for  the  four  pigs,  as  determined  directly,  for  the  ten  periods  of  this 
series  of  experiments  are  given  in  Tables  4  and  5. 

Wheat  Flour  Middlings. — It  is  evident  from  Table  4  that  the 
coefficients  of  the  digestibility  of  the  nutrients  of  wheat  flour  mid- 
dlings, when  fed  alone  in  Periods  1,  2,  7,  and  8,  varied  somewhat 


>62  BULLETIN  No.  200  [May, 

for  the  different  animals  during  the  same  experimental  period.  It  is 
also  apparent  that  the  coefficients  varied  considerably  for  the  same 
animal  in  the  different  periods.  This  is  especially  true  of  the  ether 
extract  and  the  crude  fiber.  It  is  possible  that  the  differences  in  the 
coefficients  for  Periods  1  and  2,  on  the  one  hand,  and  Periods  7  and  8, 
on  the  other  hand,  are  due  to  the  differences  in  the  age  and  the  weight 
of  the  animals.  The  pigs  were  about  four  and  one-half  months  older, 
and  weighed  about  100  pounds  more,  during  Periods  7  and  8  than  dur- 
ing Periods  1  and  2. 

The  average  coefficients  of  digestibility  of  the  nutrients  of  wheat 
flour  middlings  when  fed  alone  to  each  of  the  four  pigs  for  the  four 
ten-day  periods  (sixteen  digestion  trials)  were  as  follows:  dry  sub- 
stance, 74.4;  nitrogen-free  extract,  81.2;  crude  fiber,  21.0;  crude 
protein,  80.0 ;  and  ether  extract,  85.5. 

Ground  Corn. — The  coefficients  of  digestibility  of  the  nutrients  of 
ground  corn  fed  alone,  in  Periods  5  and  6,  varied  somewhat  for  the 
different  pigs  during  the  same  period.  The  average  coefficients  of  the 
dry  substance,  the  nitrogen-free  extract,  and  the  crude  protein  of 
the  ground  corn  agreed  very  closely  for  the  two  periods ;  the  average 
values  for  the  crude  fiber  and  the  ether  extract  did  not  vary  much. 

The  average  coefficients  of  digestibility  of  the  nutrients  of  the 
ground  corn  when  fed  alone  to  each  of  the  four  pigs  for  the  two  ten-day 
periods  (eight  digestion  trials)  were  as  follows:  dry  substance,  87.9; 
nitrogen-free  extract,  92.7 ;  crude  fiber,  30.8 ;  crude  protein,  75.0 ; 
and  ether  extract,  71.6.  The  average  coefficients  of  the  nutrients  of 
ground  corn  when  fed  alone  in  four  digestion  trials  previously  re- 
ported from  this  station1  were  as  .follows:  dry  substance,  87.7; 
nitrogen-free  extract,  93.6;  crude  fiber,  31.8;  crude  protein,  79.3; 
and  ether  extract,  71.3. 

On  comparing  the  average  coefficients  of  the  nutrients  of  the  ration 
of  ground  corn  fed  alone  with  the  corresponding  averages  for  the 
ration  of  wheat  flour  middlings  fed  alone,  it  will  be  noted  that  the 
dry  substance,  the  nitrogen-free  extract,  and  the  crude  fiber  of  the 
ground  corn  were  digested  much  more  thoroly  than  the  corresponding 
nutrients  of  the  wheat  flour  middlings  alone,  while  the  crude  protein 
and  the  ether  extract  of  the  ground  corn  were  digested  much  less 
thoroly  than  those  of  the  wheat  flour  middlings. 

Wheat  Flour  Middlings  and  Ground  Corn  (1  to  1). — The  co- 
efficients of  digestibility  of  the  nutrients  of  the  ration  of  wheat  flour 
middlings  and  ground  corn  fed  together  in  the  ratio  of  1  to  1,  in 
Periods  3  and  4,  varied  somewhat  for  the  different  animals  during  the 
same  period.  The  average  coefficients  of  digestibility  of  all  the  nutri- 
ents of  this  ration,  except  the  crude  fiber,  agreed  very  closely  for  the 
two  periods. 

Dietrich  and  Grindley:    111.  Agr.  Exp.  Sta.  Bui.  170. 


1917]  DIGESTIBILITY  OF  MIXED  FEEDS;    INDIVIDUALITY  OF  PIGS  63 

The  average  coefficients  of  digestibility  of  the  nutrients  of  the  ra- 
tion of  wheat  flour  middlings  and  ground  corn  fed  together  in  the 
ratio  of  1  to  1  to  each  of  the  four  pigs  for  the  two  ten-day  periods 
(eight  digestion  trials)  were  as  follows:  dry  substance,  79.1 ;  nitrogen- 
free  extract,  85.9 ;  crude  fiber,  12.1 ;  crude  protein,  77.3 ;  and  ether 
extract,  83.4. 

On  comparing  the  average  coefficients  of  the  nutrients  of  the  ration 
of  wheat  flour  middlings  and  ground  corn  fed  together  in  the  ratio  of 
1  to  1  with  those  of  each  of  the  rations  of  wheat  flour  middlings  and 
of  ground  corn  when  fed  alone,  it  will  be  noted  that  the  coefficients 
of  the  nutrients  for  the  ration  of  middlings  and  corn  were  in  all  cases, 
excepting  that  of  the  crude  fiber,  intermediate  between  those  of  the 
middlings  fed  alone  and  those  of  the  corn  fed  alone. 

Tankage  and  Ground  Corn  (1  to  7.5)  .—The  coefficients  of  digesti- 
bility of  the  nutrients  of  the  ration  of  tankage  and  ground  corn  fed 
together  in  the  ratio  of  1  to  7.5,  in  Periods  9  and  10,  varied  signi- 
ficantly for  the  different  pigs  during  the  same  period.  The  average 
coefficients  of  all  the  nutrients  of  this  ration,  except  the  crude  fiber, 
agreed  closely  for  the  two  experimental  periods. 

The  average  coefficients  of  digestibility  of  the  nutrients  of  the 
ration  of  tankage  and  ground  corn  fed  together  in  the  ratio  of  1  to  7.5 
to  each  of  the  four  pigs  for  the  two  ten-day  periods  (eight  digestion 
trials)  were  as  follows :  dry  substance,  86.7  ;  nitrogen-free  extract,  92.5 ; 
crude  fiber,  50.8 ;  crude  protein,  75.3 ;  and  ether  extract,  85.8.  The 
average  coefficients  of  the  nutrients  of  tankage  and  ground  corn  when 
fed  together  in  ratios  varying  from  1 :  4  to  1 :  6  in  six  digestion  trials 
previously  reported  from  this  station1  were  as  follows:  dry  sub- 
stance, 83.2 ;  nitrogen-free  extract,  92.4 ;  crude  fiber,  19.0 ;  crude  pro- 
tein, 68.7 ;  and  ether  extract,  76.4. 

On  comparing  the  coefficients  of  the  nutrients  of  this  ration  with 
those  of  wheat  flour  middlings  when  fed  alone,  it  will  be  noted  that 
the  dry  substance,  the  nitrogen-free  extract,  and  the  crude  fiber  of  the 
tankage  and  corn  were  digested  much  more  thoroly  than  those  of  the 
wheat  flour  middlings  alone,  while  the  crude  protein  was  digested  de- 
cidedly less  thoroly.  The  coefficients  of  digestibility  of  the  ether  ex- 
tract were  practically  the  same  in  the  two  rations. 

A  comparison  of  the  coefficients  of  the  nutrients  of  this  ration  with 
those  of  the  ration  of  ground  corn  fed  alone  shows  that  the  dry  sub- 
stance, the  crude  protein,  and  the  nitrogen-free  extract  of  the  tank- 
age and  corn  were  digested  practically  to  the  same  extent  as  those  of 
the  ground  corn  alone,  while  the  ether  extract  and  the  crude  fiber  of 
the  tankage  and  corn  were  digested  much  more  thoroly  than  those  of 
the  ground  corn  alone. 

'Dietrich  and  Grindley:    111.  Agr.  Exp.  Sta.  Bui.  170. 


64 


BULLETIN  No.  200 


[May, 


TABLE  4. — COEFFICIENTS  OF  DIGESTIBILITY 


Pig 

Dry 

substance 

Nitrogen- 
free 
extract 

Crude 
fiber 

Crude 
protein 

Ether 
extract 

First  Test  Period.     December  18  to  27,  1913.     Ten  days.     Middlings 


113 

75.3 

83.5 

21.5 

78.7 

82.0 

213 

73.7 

82.3 

20.3 

77.5 

77.7 

313 

76.1 

83.8 

23.9 

80.5 

83.0 

413 

74.9 

82.7 

25.5 

77.9 

80.7 

Average 

75.0 

83:.! 

22.8 

78.7 

80.9 

Second  Test  Period.  December  28,  1913  to  January  6,  1914.     Ten  Days.  Middlings 


113 

75.3 

82.6 

22.3 

80.1 

87.2 

213 

74.2 

81.7 

19.6 

79.6 

82.5 

313 

74.4 

81.3 

14.9 

82.5 

85.8 

413 

73.4 

79.7 

34.1 

77.6 

79.6 

Average 

74.3 

81.3 

22.7 

80.0 

83.8 

Third  Test  Period.     January  24  to  February  2,  1914.     Ten  days.     Middlings  and 

ground  corn  (1  to  1) 


113 

79.1 

85.5 

19.2 

78.2 

78.3 

213 

78.8 

85.4 

22.1 

76.5 

78.6 

313 

80.3 

86.7 

12.0 

81.6 

87.4 

413 

79.6 

86.7 

13.0 

75.1 

88.2 

Average 

79.5 

86.1 

16.6 

77.9 

83.1 

Fourth  Test  Period.     February  3  to  12,  1914.     Ten  days.     Middlings  and  ground 

corn  (1  to  1) 


113 

78.5 

86.3 

0.2 

78.1 

77.9 

213 

79.0 

85.5 

17.5 

76.4 

84.1 

313 

79.0 

86.1 

3.0 

78.2 

87.0 

413 

78.3' 

85.4 

9.6 

74.0 

86.1 

Average 

78.7 

85.8 

7.6 

76.7 

83.8 

Fifth  Test  Period.     March  7  to  17,   1914.     Ten  days.     Ground  corn 


113 

88.7 

93.1 

27.2 

76.8 

83.2 

213 

86.6 

92.5 

21.4 

71.7 

57.3 

313 

88.2 

92.4 

40.1 

76.2 

79.2 

413 

88.5 

93.5 

29.9 

76.5 

63.4 

Average 

88.0 

92.9 

29.7 

75.3 

70.8 

Sixth  Test  Period.     March  18  to  27,  1914.     Ten  days.  Ground  corn 


113 

88.0 

92.2 

34.2 

77.1 

82.3 

213 

86.3 

92.0 

20.3 

70.8 

64.8 

313 

88.9 

93.4 

42.9 

76.3 

72.1 

413 

87.4 

92.2 

30.4 

74.9 

70.8 

Average 

87.7 

92.5 

32.0 

74.8 

72.5 

1917]  DIGESTIBILITY  OF  MIXED  FEEDS;    INDIVIDUALITY  OF  PIGS 

TABLE  4. — Concluded 


65 


Pig 

Dry 

substance 

Nitrogen- 
free 
extract 

Crude 
fiber 

Cru3e 
protein 

Ether 
extract 

Seventh  Test  Period.     April  26  to  May  5,  1914.     Ten  days.     Middlings 

113 
213 
313 
413 

Average 

73.3 
73.2 
74.9 
72.1 

73.4 

79.8 
78.5 
80.1 
78.4 

79.2 

15.5 
26.0 
18.3 
15.3 

18.8 

79.5 
79.1 
83.3 

78.4 

80.1 

89.0 

88.5 
87.8 
85.8 

87.8 

Eighth  Test  Period.     May  6  to  15,  1914.     Ten  days.     Middlings 


113 

75.4 

82.0 

18.1 

80.8 

92.8 

213 

74.7 

80.9 

19.5 

80.7 

89.7 

313 

74.8 

81.1 

19.8 

82.6 

88.1 

413 

74.9 

81.2 

21:0 

80.2 

86.7 

Average 

75.0 

81.3 

19.6 

81.1 

89.3 

Ninth  Test  Period.     June  5  to  14,  1914.     Ten  days. 

corn  (1  to  7.5) 


Tankage  and  ground 


113 

87.3 

92.6 

49.9 

78.1 

86.7 

213 

86.0 

92.1 

41.1 

73.1 

87.7 

313 

87.5 

93.3 

53.9 

75.0 

92.3 

413 

85.5 

91.5 

44.7 

73.9 

80.1 

Average 

86.6 

92.4 

47.4 

75.0 

86.7 

Tenth  Test  Period.     June  15  to  24,  1914.     Ten  days. 

corn  (1  to  7.5) 


Tankage  and  ground 


113 

86.7 

92.2 

52.8 

76.9 

86.6 

213 

85.4 

91.5 

49.2 

73.1 

82.6 

313 

88.5 

94.0 

60.4 

77.0 

87.6 

413 

87.1 

92.8 

54.6 

75.2 

83.0 

Average 

86.9 

92.6 

54.3 

75.6 

85.0 

THE  INFLUENCE  OF  ONE  FEED  UPON  THE  DIGESTIBILITY  OF  THE 
NUTRIENTS  OF  ANOTHER  FEED 

The  doubtful  values  obtained  in  digestion  experiments  in  our 
previous  work  and  in  the  work  of  others,  by  determining  indirectly, 
or  by  calculation,  the  coefficients  of  the  nutrients  for  one  feed  by  sub- 
tracting the  weights  of  the  digestible  nutrients  of  another  feed  from 
the  corresponding  values  for  the  two  feeds  combined,  led  us  to  plan 
these  experiments  to  determine  more  accurately,  if  possible,  the  in- 
fluence of  one  feed  upon  the  digestibility  of  the  nutrients  of  another 
feed. 

From  the  results  of  practical  feeding  experiments  some  authors 
have  taken  the  view  that  when  feeds  are  fed  singly,  they  are  not  as 
completely  digested  as  when  fed  in  mixed  rations,  because  rations  com- 
posed of  a  single  feed  are  not  as  efficient  for  producing  growth  and 
fattening  as  mixed  feeds.  For  example,  whenever  milk  is  added  to  a 


66 


BULLETIN  No.  200 


[May, 


TABLE  5.— SUMMARY  OF  THE  AVERAGE  COEFFICIENTS  OF  DIGESTIBILITY 
CF  THE  EATIONS 


Period 

Dry 
sub- 
stance 

Nitro- 
gen-free 
extract 

Crude 
fiber 

Crude 
protein 

Ether 
extract 

Wheat  flour  middlings  

1 

75.0 

83.1 

22.8 

78.7 

80.9 

Wheat  flour  middlings  

2 

74.3 

81.3 

22.7 

80.0 

83.8 

Average  

74.6 

82.2 

22.7 

79.3 

82.3 

Wheat  flour  middlings  

7 

73.4 

79.2 

18.8 

80.1 

87.8 

Wheat  flour  middlings  

8 

75.0 

81.3 

19.6 

81.1 

89.3 

Average  

74.2 

80.2 

19.2 

80.6 

88.5 

Ground  corn  and  middlings  

3 

79.5 

86.1 

16.6 

77.9 

83.1 

Ground  corn  and  middlings  

4 

78.7 

85.8 

7.6 

76.7 

83.8 

Average  

79.1 

85.9 

12.1 

77.3 

83.4 

Ground  corn  

5 

88.0 

92.9 

29.7 

75.3 

70.8 

Ground  corn  

6 

87.7 

'92.5 

32.0 

74.8 

72.5 

Average  

87  8 

92  7 

30  8 

75.0 

71.6 

Tankage  and  ground  corn  

9 

86  6 

92  4 

474 

750 

86  7 

Tankage  and  ground  corn  

10 

869 

92.8 

543 

75.6 

85  0 

Average.  . 

86.7 

92.6 

50.8 

75.3 

85.8 

ration  composed  of  a  single  grain,  a  larger  amount  of  pork  is  produced 
than  when  the  same  amount  of  nutrients  from  the  single  grain  is  fed. 
It  has  therefore  been  assumed  by  some  authors  that  in  such  cases  the 
increased  production  is  due  to  the  fact  that  the  milk  increased  the 
digestibility  of  the  grains  with  which  it  was  fed.  However,  it  has 
recently  been  proved  that  there  are  other  factors  that  favor  increased 
production  where  the  mixed  rations  are  fed. 

The  data  for  the  coefficients  of  digestibility  of  the  nutrients  of  the 
wheat  flour  middlings,  as  determined  directly  when  fed  alone,  and  as 
calculated  indirectly  from  the  results  of  direct  digestion  experiments 
with  the  ration  of  middlings  and  ground  corn  and  of  the  ground  corn 
alone,  are  given  in  Table  6.  It  will  be  noted  that  the  individual  data 
and  the  average  data  for  the  four  pigs  show  that  the  calculated  values 
indirectly  determined  for  the  coefficients  of  digestibility  of  the  dry 
substance  and  the  nitrogen-free  extract  of  the  middlings  are  signifi- 
cantly lower  than  the  corresponding  coefficients  of  the  nutrients  of  the 
middlings  determined  directly  by  the  digestion  experiments. 

The  results  indicate  that  there  is  no  significant  difference  between 
the  coefficients  for  the  protein  as  calculated  indirectly  and  as  deter- 
mined directly.  The  results  for  the  ether  extract  are  very  irregular, 
but  the  average  results  indicate  that  the  calculated  values  for  the  co- 
efficients of  the  ether  extract  for  the  middlings  are  probably  signifi- 
cantly higher  than  those  determined  directly  by  actual  experiments. 
It  is  quite  apparent  from  the  experimental  data  here  presented  that 
the  calculated  coefficients  for  the  crude  fiber  are  very  irregular  as 
compared  with  those  determined  directly. 


1917]  DIGESTIBILITY  OF  MIXED  FEEDS;    INDIVIDUALITY  OF  PIGS 

TABLE  6. — COEFFICIENTS  OF  DIGESTIBILITY  OF  MIDDLINGS,  DIRECTLY  AND 
INDIRECTLY  DETERMINED 


67 


Pig 

Dry 

substance 

Nitrogen- 
free  extract 

Crude  fiber 

Crude 
protein 

Ether 
extract 

Middlings  fed  alone.     First  Test  Period 


113 

75.3 

83.5 

21.5 

78.7 

82.0 

213 

73.7 

82.3 

20.3 

77.5 

77.7 

313 

76.1 

83.8 

23.9 

80.5 

83.0 

413 

74.9 

82.7 

25.5 

77.9 

80.7 

Average 

75.0 

83.1 

22.8 

78.7 

80.8 

Middlings  calculated  from  middlings  and  corn  ration.     Third  and  Fifth 

Test  Periods 


113 

69.9 

75.6 

16.6 

78.9 

75.9 

213 

71.4 

76.1 

22.4 

78.7 

89.0 

313 

72.2 

79.3 

3.0 

84.1 

91.4 

413 

71.1 

77.7 

7.6 

74.4 

100.3 

Average 

71.2 

77.2 

12.4 

79.0 

89.2 

Middlings  fed  alone.    Second  Test  Period 


113 

75.3 

82.6 

22.3 

80.1 

87.2 

213 

74.2 

81.7 

19.6 

79.6 

82.5 

313 

74.4 

81.3 

14.9 

82.5 

85.4 

413 

73.4 

79.7 

34.1 

77.6 

79.6 

Average 

74.3 

81.3 

22.7 

79.9 

83.7 

Middlings  calculated  from  middlings  and  corn  ration.     Fourth  and  Sixth 

Test  Periods 


113 

69.5 

78.8 

-10.7 

78.5 

75.9   v 

213 

.       71.9 

76.9 

16.7 

79.0 

93.6 

313 

69.5 

76.5 

-9.8 

79.1 

94.3 

413 

69.8 

76.6 

2.9 

73.5 

93.6 

Average 

70.2 

77.a 

-0.2 

77.5 

89.3 

The  data  for  the  coefficients  of  digestibility  of  the  nutrients  of  the 
ground  corn  as  determined  directly  when  fed  alone,  and  as  calculated 
indirectly  from  the  direct  experiments  with  the  combined  ration  com- 
posed of  middlings  and  ground  corn  and  the  wheat  flour  middlings 
alone,  are  given  in  Table  7.  A  study  of  these  data  leads  in  general  to 
the  same  conclusions  as  to  the  variations  and  differences  between  the 
direct  and  indirect  coefficients  of  the  nutrients  of  the  ground  corn  as 
were  reached  with  regard  to  the  direct  and  indirect  values  for  wheat 
flour  middlings.  It  should  be  said,  however,  that  the  calculated  co- 
efficients for  the  crude  fiber  and  the  ether  extract  of  the  corn  are  more 
irregular  than  the  corresponding  calculated  coefficients  for  the  wheat 
flour  middlings. 

The  data  for  the  coefficients  of  digestibility  of  the  nutrients  of  the 
ration  composed  of  one  part  of  middlings  and  one  part  of  ground 


68 


BULLETIN  No.  200 


[May, 


corn,  as  determined  directly,  and  as  calculated  indirectly  from  the 
coefficients  directly  determined  for  middlings  when  fed  alone  and  for 
ground  corn  when  fed  alone,  are  given  in  Table  8.  It  is  apparent  that 
the  calculated  coefficients  for  the  ether  extract  of  the  ration  are  lower 
than  those  directly  determined  for  the  mixed  ration.  There  is  appar- 
ently no  significant  difference  between  the  calculated  coefficients  and 
the  directly  determined  coefficients  for  the  protein  of  the  mixed  ration. 
It  is  thus  evident  from  the  individual  data,  as  well  as  from  the 
average  results  given  in  Tables  6  to  8,  inclusive,  that  the  digestibility 
of  the  nutrients  of  a  ration  composed  of  equal  parts  of  wheat  flour 
middlings  and  ground  corn  are  not  what  they  would  be  if  the  coeffi- 
cients of  digestibility  of  the  nutrients  of  each  of  the  feeds  when  fed 
together  had  remained  the  same  as  they  were  in  the  individual  feeds 
when  fed  alone.  This  difference  between  the  directly  and  indirectly 

TABLE  7. — COEFFICIENTS  OF  DIGESTIBILITY  OF  GROUND  CORN,  DIRECTLY  AND 
INDIRECTLY  DETERMINED 


Pig 


Dry 

substance 


Nitrogon- 

free 
extract 


Crude 
fiber 


Crude 
protein 


Ether 
extract 


Ground  corn  fed  alone.     Fifth  Test  Period 


113 

88.7 

93.1 

27.2 

76.8 

83.2 

213 

86.6 

92.5 

21.4 

71.7 

57.3 

313 

88.2 

92.4 

40.1 

76.2 

79.2 

413 

88.5 

93.5 

29.9 

76.5 

63.4 

Average 

88.0 

92.9 

29.6 

75.3 

70.8 

'   Ground  corn  calculated  from  middlings  and  corn  ration.     First  arid  Third 

Test  Periods 


113 

83.0 

87.1 

12.0 

77.4        |             70.8 

213 

84.2 

87.7 

27.7 

74.5 

80.4 

313 

84.8 

89.0 

-25.3 

83.9 

96.5 

413 

84.5 

89.7 

-26.0 

69:0 

103.6 

Average 

84.1 

88.4 

-2.9 

76.2 

87.8 

Ground  corn  fed  alone.     Sixth  Test  Period 


113 

88.0 

92.2 

34.2 

77.1 

82.3 

213 

86.3 

92.0 

20.3 

70.8 

64.8 

313 

88.9 

93.4 

42.9 

76.3 

72.1 

413 

87.4 

92.2 

30.4 

74.9 

70.8 

Average 

87.6 

92.4 

31.9 

74.8 

72.5 

Ground  corn  calculated  from  middlings  and  corn  ration.     Second  and  Fourth 

Test  Periods 


113 

81.9 

89.2 

-69.0 

73.9 

58.8 

213 

84.0 

88.4 

11.2 

69.6 

87.6 

313 

83.7 

89.7 

-34.2 

69.6 

89.0 

413 

83.4 

89.8 

-67.0 

66.2 

99.5 

Average 

83.3 

89.3 

-39.8 

69.8 

83.7 

1917} 


DIGESTIBILITY  OF  MIXED  FEEDS;    INDIVIDUALITY  OF  PIGS 


69 


TABLE  8.- 


-COEFFICIENTS  OF  DIGESTIBILITY  OF  A  RATION  OF  MIDDLINGS  AND  GROUND 
CORN  (1  TO  1),  DIRECTLY  AND  INDIRECTLY  DETERMINED 


Pig 

Dry 
substance 

Nitrogen- 
free  extract 

Crude  fiber 

Crude 
protein 

Ether 
extract 

Middlings  and  ground  corn  (1  to  1)  fed  together,  direct  determination. 
Third  Test  Period 


113 

79.1 

85.5 

19.2 

78.2 

78.3 

213 

78.8 

85.4 

22.1 

76.5 

78.6 

313 

80.3 

86.7 

12.0 

81.6 

87.4 

413 

79.6 

86.7 

13.0 

75.1 

88.2 

Average 

79.5 

86.1 

16.G 

77.9 

83.1 

Middlings  and  ground  corn  (1  to  1)  calculated  from  the  direct  determinations 
of  the  middlings  ration  and  the  corn  ration.    First  and  Fifth  Test  Periods 


113 

81.9 

88.9 

22.9 

78.1 

82.4 

213 

80.0 

88.1 

20.6 

75.7 

70.9 

313 

82.0 

88.7 

27.9 

79.1 

81.7 

413 

81.6 

88.8 

26.6 

77.5 

74.9 

Average 

81.4 

88.6 

24.5 

77.6 

77.5 

Middlings  and  ground  corn  (1  to  1)  calculated  from  the  indirect  determinations  for 

the  corn  ration  and  the  middlings  ration  (see  second  sections  of 

Tables  6  and  7) 


113 

76.3 

82.1 

15.5 

78.4 

74.2 

213 

77.7 

82.7 

23.7 

77.4 

86.1 

313 

78.4 

84.8 

-4.0 

84.0 

93.1 

413 

77.7 

84.5 

-0.7 

72.7 

101.4 

Average 

77.5 

83.5 

8.6 

78.1 

88.7 

Middlings  and  ground  corn   (1  to  1)   fed  together,  direct  determination. 
Fourth  Test  Period 


113 

78.5 

86.3 

0.2 

78.1 

77.9 

213 

79.0 

85.5 

17.6 

76.4 

84.1 

313 

79.0 

86.1 

3.0 

78.2 

87.0 

413 

78.3 

85.4 

9.6 

74.0 

86.1 

Average 

78.7 

85.8 

7.6 

76.7 

83.8 

Middlings  and  ground  corn  (1  to  1)  calculated  from  the  direct  determinations  of 
the  corn  ration  and  the  middlings  ration.    Second  and  Sixth  Test  Periods 


113 

81.5 

88.0 

25.2 

79.2 

85.6 

213 

80.1 

87.5 

19.8  , 

76.8 

76.6 

313 

81.5 

88.2 

21.8 

80.5 

81.2 

413 

80.3 

86.8 

33.2 

76.7 

76.6 

Average 

80.8 

87.6 

25.0 

78.3 

80.0 

Middlings  and  ground  corn  (1  to  1)  calculated  from  the  indirect  determinations  foi 

the  corn  ration  and  the  middlings  ration  (see  fourth  sections 

of  Tables  6  and  7) 


113 

75.6 

84.7 

-25.1 

77.0 

70.2 

213 

77.8 

83.4 

15.3 

76.0 

91.6 

313 

76.5 

84.0 

-15.8 

75.9 

92.5 

413 

76.5 

84.1 

-14.4 

71.2 

95.6 

Average 

76.6 

84.0 

-10.0 

75.0 

87.5 

70  BULLETIN  No.  200  [May, 

determined  coefficients  of  the  nutrients  of  the  mixed  ration  may  be 
due  to  one  or  the  other  of  the  following  influences :  First,  it  is  pos- 
sible that  either  the  wheat  flour  middlings  or  the  ground  corn  in  the 
mixed  ration  influences  directly  the  digestibility  of  the  nutrients  of  the 
other  feed.  Second,  it  is  possible,  on  the  other  hand,  that  there  is  a 
mutual  influence  of  each  feed  upon  the  other,  which  results  in  decreas- 
ing the  digestibility  of  the  dry  substance,  the  nitrogen-free  extract, 
and  the  crude  fiber;  and  in  increasing  the  digestibility  of  the  ether 
extract  of  the  mixed  ration. 

INDIVIDUALITY  OF  PIGS  AS  TO  THE  THORONESS  WITH  WHICH  THEY 

DIGEST  THEIR  FEED 

From  the  preceding  results  it  was  possible  to  study  the  question  of 
the  individuality  of  pigs  as  to  the  thoroness  with  which  they  digest 
their  feed.  The  influence  of  the  individual  peculiarities  of  experi- 
mental animals  upon  the  thoroness  of  digestion  of  their  feed  is  a  mat- 
ter of  considerable  interest.  Very  often  when  the  same  ration  is  fed 
to  three  or  more  animals  of  the  same  species,  as  many  different  coeffi- 
cients of  digestibility  are  obtained  for  the  same  nutrient  as  there  are 
animals.  The  variations  are  usually  not  great,  but  they  nearly  always 
occur,  and  the  question  arises  as  to  the  part  which  the  factor  of  indi- 
viduality plays  in  producing  these  variations. 

The  data  for  the  coefficients  of  digestibility  of  the  crude  protein 
obtained  in  forty  digestion  trials,  of  ten  days  each,  in  which  four 
rations  were  fed  to  each  of  four  pigs,  are  given  in  Table  9.  Examina- 
tion of  the  data  shows  that  the  individual  coefficients  for  Pig  313  are 
significantly  greater  than  the  individual  coefficients  for  Pig  213,  in 
each  of  the  ten  experimental  periods.  A  similar  comparison  of  the 
coefficients  of  digestibility  of  protein  for  Pigs  313  and  413  shows  a 
similar  significant  difference.  Since  conditions  thruout  the  experi- 
ment were  practically  identical,  the  data  lead  clearly  to  the  conclu- 
sion that,  altho  the  pigs  were  litter  mates  and  were  fed  together  from 
birth,  individuality  was  shown  by  a  distinct  and  well-defined  differ- 
ence between  the  coefficients  of  digestibility  of  crude  protein  for 
Pig  313  and  Pigs  213  and  413  thruout  the  ten  experiments.  A  fur- 
ther study  of  the  data  in  this  table  shows  that  for  Pigs  113  and  213 
and  for  Pigs  113  and  413  there  was  a  considerable,  tho  less  marked, 
difference  in  the  coefficients  of  digestibility  of  crude  protein  which 
apparently  can  be  assigned  to  the  factor  of  individuality;  but  that 
there  are  practically  no  differences  in  the  coefficients  of  digestibility  of 
crude  protein  for  Pigs  213  and  413  or  for  Pigs  113  and  313,  that  can 
be  considered  as  due  to  the  factor  of  individuality. 

Examination  of  the  data  given  in  Table  9  for  the  coefficients  of  the 
dry  matter,  the  nitrogen-free  extract,  and  the  ether  extract  shows  in 
general  the  same  individual  differences  as  were  found  in  the  coeffi- 


19171 


DIGESTIBILITY  OF  MIXED  FEEDS;.    INDIVIDUALITY  OF  PIGS 


71 


TABLE  9. — SUMMARY  OF  THE  COEFFICIENTS  OF  DIGESTIBILITY  OF  THE  NUTRIENTS 

SHOWING  THE  INDIVIDUALITY  OF  PIGS  AS  TO  THE  THORONESS 

WITH  WHICH  THEY  DIGESTED  THEIR  FEED 


Period 

Ration 

Pig 
313 

Pig 
113 

Pig 

413 

Pig 
213 

Pig 
313 

Pig 
113 

Pig 
413 

Pig 
213 

Crude  protein 

Ether  extract 

1 
2 
7 
8 
3 
4 
5 
6 
9 
10 

Middlings  (alone)  
Middlings  (alone)  

80.5 
82.5 
83.3 
82.6 
81.6 
78.2 
76.2 
76.3 
75.0 
77.0 
79.3 

78.7 
80.1 
79.5 
80.8 
78.2 
78.1 
76.8 
77.1 
78.1 
76.9 
78.4 

77.9 
77.6 
78.4 
80.2 
75.1 
74.0 
76.5 
74.9 
73.9 
75.2 
76.4 

77.5 
79.6 
79.1 
80.7 
76.5 
76.4 
71.7 
70.8 
73.1 
73.1 
75.8 

83.0 
85.8 
87.8 
88.1 
87.4 
87.0 
79.2 
72.1 
92.3 
87.6 
85:0 

82.0 
87.2 
89.0 
92.8 
78.3 
77.9 
83.2 
82.3 
86.7 
86.6 
84.6 

80.7 
79.6 
85.8 
86.7 
88.2 
86.1 
63.4 
70.8 
80.1 
83.0 
80.4 

77.7 
82.5 
88.5 
89.7 
78.6 
84.1 
57.3 
64.8 
87.7 
82.6 
79.3 

Middlings  (alone)  

Middlings  (alone)  

Middlings  and  corn  (1  to  1)  ... 
Middlings  and  corn  (1  to  1)  ... 
Corn  (alone)  

Corn  (alone)  

Tankage  and  corn  (1  to  7.5)  .... 
Tankage  and  corn  (1  to  7.5)  .... 
Average  

Dry  substance         |  Nitrogen-free  extract 

1 
2 
7 
8 
3 
4 
5 
6 
9 
10 

Middlings  (alone)  

76.1 
74.4 
74.9 

74.8 
80.3 
79.0 
88.2 
88.9 
87.5 
88.5 
81  3 

75.3 
75.3 
73.3 

75.4 
79.1 

78.5 
88.7 
88.0 
87.3 
86.7 
808 

74.9 
73.4 
72.1 
74.9 
79.6 
78.3 
88.5 
87.4 
85.5 
87.1 
80?, 

73.7 
74.2 
73.2 
74.7 
78.8 
79.0 
86.6 
86.3 
86.0 
85.4 
798 

83.8 
81.3 
80.1 
81.1 
86.7 
86.1 
92.4 
93.4 
93.5 
94.2 
873 

83.5 
82.6 
79.8 
82.0 
85.5 
86.3 
93.1 
92.2 
92.8 
92.5 
87.0 

82.7 
7-9.7 
78.4 
81.2 
86.7 
85.4 
93.5 
92.2 
91.7 
93.1 
865 

82.3 
81.7 
78.5 
80.9 
85.4 
85.5 
92.5 
92.0 
92.4 
91.8 
863 

Middlings  (alone)  

Middlings  (alone)  

Middlings  (alone)  

Middlings  and  corn  (1  to  1)  ... 
Middlings  and  corn  (1  to  1)  ... 
Corn  (alone)  

Corn  (alone)  

Tankage  and  corn  (1  to  7.5)  .... 
Tankage  and  corn  (1  to  7.5)  .... 
Average  .  . 

eients  of  digestibility  of  the  crude  protein  for  the  four  pigs.  How- 
ever, the  individuality  of  these  pigs  with  reference  to  their  power  of 
digesting  dry  matter,  nitrogen-free  extract,  and  ether  extract  is  not 
so  clearly  evident  as  it  was  in  the  case  of  crude  protein. 

It  is  apparent,  therefore,  that  in  this  series  of  experiments,  all  with 
the  same  animals,  in  which  different  rations  were  used  in  the  different 
experiments,  the  coefficients  as  a  whole  showed  constantly  higher 
values  for  some  animals  than  for  other  animals.  Such  consistent  dif- 
ferences under  such  conditions  must  be  attributed  to  the  individuality 
of  the  different  animals. 

The  total  gains  in  weight  of  the  four  pigs  during  the  ten  experi- 
mental periods,  each  of  ten  days'  duration,  during  which  time  each 
of  the  four  animals  received  the  same  kinds  of  feed  and  the  same  quan- 
tities of  feed  per  100  pounds  of  live  weight,  were  as  follows :  Pig  113, 
79  pounds ;  Pig  213,  74  pounds ;  Pig  313,  57  pounds ;  and  Pig  413, 
65  pounds.  The  average  live  weights  of  the  pigs  during  the  ten  ex- 
perimental periods  were  as  follows :  Pig  113,  250.5  pounds ;  Pig  213, 
250.8  pounds ;  Pig  313,  214.3  pounds ;  and  Pig  413,  211.0  pounds. 
The  weights  of  the  total  feeds  consumed  during  this  same  time  were 
as  follows :  Pig  113,  503.2  pounds ;  Pig  213,  503.2  pounds ;  Pig  313, 
423.2  pounds;  and  Pig  413,  423.2  pounds.  The  weights  of  feed  re- 


72  BULLETIN  No.  200  [May, 

quired  to  produce  100  pounds  of  gain  during  the  ten  experimental 
periods  were  as  follows:  Pig  113,  637  pounds;  Pig  218,  680  pounds; 
Pig  313,  743  pounds;  and  Pig  413,  651  pounds.  Comparing  these 
gains  in  weight  and  the  economy  of  the  gains  in  weight  with  the  aver- 
age coefficients  of  digestibility  of  the  nutrients  of  the  feeds  for  each 
animal,  it  will  be  noted  that  there  is  no  consistent  correlation  between 
the  coefficients  of  digestibility  and  the  gains,  or  the  economy  of  gains, 
in  weight.  For  example,  Pig  113,  which  on  the  average  digested  all 
of  the  nutrients  of  the  feeds  more  thoroly  than  did  Pig  213  (which 
weighed  the  same  and  consumed  an  equal  quantity  of  the  same  feeds 
as  Pig  113)  made  a  gain  of  79  pounds  and  required  637  pounds  of 
feed  to  produce  100  pounds  of  gain ;  while  Pig  213  gained  74  pounds 
and  required  680  pounds  of  feed  to  produce  100  pounds  of  gain.  On 
the  other  hand,  Pig  313,  which  on  the  average  digested  all  of  the 
nutrients  of  the  feeds  more  thoroly  than  did  Pig  413  (which  weighed 
the  same  and  consumed  an  equal  quantity  of  the  same  feeds  as  Pig 
313)  made  a  gain  of  only  57  pounds  and  required  743  pounds  of  feed 
to  produce  100  pounds  of  gain ;  while  Pig  413  gained  65  pounds  and 
required  651  pounds  of  feed  to  produce  100  pounds  of  gain. 

This  study  clearly  shows  that  different  animals  of  the  same  species 
may  show  individuality  as  to  the  thoroness  with  which  they  digest  the 
nutrients  of  their  feeds.  However,  such  differences  in  the  coefficients 
of  digestibility  of  the  nutrients  of  the  same  feeds  by  different  animals 
are  probably  too  'small  to  be  considered  of  practical  or  economic  im- 
portance. 

SECOND  SERIES  OF  EXPERIMENTS,  1914-1915 
PLAN 

Four  cross-bred  Duroc  Jersey-Poland  China  barrows  of  the  same 
age  as  the  pigs  used  in  the  first  series  of  experiments — namely,  a  few 
days  over  seven  months,  and  all  from  the  same  litter — were  selected 
for  this  second  series  of  experiments.  The  pens,  feed  troughs,  and 
digestion  harness  were  the  same  as  those  used  in  the  first  experiments. 
In  the  second  series  ground  barley  (malting)  was  substituted  for  the 
wheat  flour  middlings  used  in  the  first  series,  but  the  ratio  of  feed  to 
the  live  weight  of  the  animals,  the  length  of  the  transitional,  the  pre- 
liminary, and  the  test  periods,  and  the  general  management  and  treat- 
ment of  the  animals  were  the  same.  The  weather  conditions  during 
Ihe  two  series  of  experiments  were  also  similar. 

The  first  ration  for  which  the  coefficients  of  digestibility  were  de- 
termined consisted  of  2.08  pounds  of  ground  barley  (malting)  per 
]00  pounds  live  weight;  the  second,  of  1.05  pounds  of  ground  barley 
and  1.05  pounds  of  ground  corn  (No.  2  yellow)  per  100  pounds  live 
weight ;  the  third,  of  2.12  pounds  of  ground  corn  per  100  pounds  live 
weight;  and  the  fourth,  of  1.80  pounds  of  ground  corn  and  0.24 
pounds  of  digester  tankage  per  100  pounds  live  weight.  Each  of  these 


1917} 


DIGESTIBILITY  OF  MIXED  FEEDS;    INDIVIDUALITY  OF  PIGS 


73 


rations  was  fed  for  two  ten-day  periods,  during  which  time  samples  of 
the  feeds  and  the  feces  were  taken  for  chemical  analysis. 

CHEMICAL  COMPOSITION  OF  FEEDS  AND  FECES;  AND  WEIGHTS  OF  PIGS, 
FEEDS,  WATER,  FECES,  AND  URINE 

The  chemical  composition  of  the  feeds  and  the  fresh  feces  are  given 
in  Tables  10  and  12,  respectively.  The  weights  of  the  pigs,  the  feeds, 
the  water,  the  feces,  and  the  urine  are  presented  in  Table  11. 

From  the  experimental  data  given  in  Table  11,  it  will  be  noted 
that  the  weights  of  the  feces  per  pound  of  feed  varied  markedly  de- 
pending upon  the  character  of  the  ration.  Thus  the  average  weights 
of  the  fresh  feces  per  pound  of  feed  were  as  follows:  in  Periods  1 
and  2,  in  which  ground  barley  was  fed,  0.96  pound;  in  Periods  3 
and  4,  in  which  ground  barley  and  ground  corn  in  the  ratio  of  1  to  1 
were  fed,  0.68  pound;  in  Periods  7  and  8,  in  which  tankage  and 
ground  corn  in  the  ratio  of  1  to  7.5  were  fed,  0.41  pound;  and  in 
Periods  5  and  6,  in  which  ground  corn  was  fed,  0.36  pound. 

Examination  of  the  data  of  Table  12,  giving  the  composition  of 
the  fresh  feces,  and  of  Table  13,  showing  the  coefficients  of  digestibil- 
ity of  the  nutrients  of  the  rations,  shows  that  the  differences  mentioned 
above  in  the  weights  of  the  feces  per  pound  of  feed  due  to  the  charac- 
ter of  the  ration  consumed  can  be  traced,  in  large  part  at  least,  as  in 
the  first  experiments,  to  the  variations  in  the  water  content  of  the 
feces,  and  to  the  variations  in  the  coefficients  of  digestibility  of  the 
dry  substance  of  the  rations.  Thus,  the  average  water  content  of  the 
feces  for  the  several  periods  was  as  follows :  Periods  1  and  2,  in  which 
ground  barley  alone  was  fed,  72.20  percent ;  Periods  3  and  4,  in  which 
ground  barley  and  ground  corn  in  the  ratio  of  1  to  1  were  fed,  74.91 
percent;  Periods  7  and  8,  in  which  tankage  and  ground  corn  in  the 
ratio  of  1  to  7.5  were  fed,  68.81  percent ;  and  Periods  5  and  6,  in  which 
ground  corn  alone  was  fed,  67.74  percent.  The  average  coefficients  of 

TABLE  10. — CHEMICAL  COMPOSITION  OF  THE  FEEDS 
(Eesults  expressed  in  percent  of  the  fresh  substance) 


Kind  of  feed 

Used 
in 
periods 

Dry 
sub- 
stance 

Nitro- 
gen-free 
extract 

Crude 
fiber 

Crude 
protein 

Ether 

extract 

Crude 
ash 

Total 
nitro- 
gen 

Ground  corn.  . 
Ground  corn.  . 
Ground  corn.  . 
Average.  .  .  . 

Barley  

3,4 
5,6 

7,8 

1,2 

86.32 
83.94 
86.22 
85^49 

91.00 

69.85 
68.17 
71.37 
69.80 

67  06 

3.73 

2.06 
2.29 
2.69 

402 

9.51 
9.15 
9.31 
9.32 

14  80 

3.73 
3.37 
2.06 
3.05 

2  35 

1.17 
1.18 
1.19 
1.18 

2  77 

1.522 
1.464 
1.489 
1.492 

2  368 

Barlev  

3,4 

91.07 

70.04 

496 

11  29 

2  14 

2  65 

1  806 

Average.  .  .  . 
Tankage.  . 

7.8 

91.03 

88.65 

68.55 
12.51 

4.49 
5.33 

13.04 
58.53 

2.24 
8.15 

2.71* 
15.49 

2.087 
9.364 

BULLETIN  No.  200 

TABLE  11. — WEIGHTS  OP  PIGS,  FEEDS,  WATER,  FECES,  AND  URINE 
(Results  expressed  in  pounds) 


[May, 


Feeds  consumed 

Per 

Feces 

Live 

day 

Total 

per 

Total 

Pig 

weight 

Ground 

per 

Water 

feces 

Ib.of 

urine 

Barley 

corn 

Total 

100  Ibs. 

feed 

live 

weight 

First  Test  Period.     November  27  to  December  6,  1914.     Ten  days.     Barley 


114 
214 
314 
414 

Average 

217.1 
182.4 
174.1 
158.9 

183.1 

45.00 
38.40 
37.40 
33.00 

38.45 

45.00 
38.40 
37.40 
33.00 

38.45 

2.07 
2.11 
2.15 
2.08 

2.10 

143.40 
122.40 
119.00 
105.00 

'  122.45 

39.01 
36.23 
35.33 
32.17 

35.68 

0.87 
0.94 
0.94 
0.97 

0.93 

100.76 
83.41 
80.12 
68.39 

83.17 

Second  Test  Period.    December  7  to  16,  1914.    Ten  days.    Barley 

114 
214 
314 
414 

Average 

222.9 
187.4 
177.9 
162.4 

187.6 

45.00 
38.40 
37.40 
33.00 

38.45 

::::: 

45.00 
38.40 
37.40 
33.00 

38.45 

2.02 
2.05 
2.10 
2.03 

2.05 

143.40 
122.40 
119.00 
105.00 

122.45 

41.92 
37.07 
37.42 
34.99 

37.85 

0.93 
0.97 
1.00 
1.06 

0.99 

106.27 
86.00 
74.54 
67.97 

83.69 

..... 

Third  Test  Period.    January  17  to  26,  1915.     Ten  days.    Barley  and  ground  corn 

(1  to  1) 


114 

242.6 

26.00 

26.00 

52.00 

2.14 

164.00 

33.60 

0.65 

133.64 

214 

203.6 

21.50 

21.50 

43.00 

2.11 

136.00 

30.31 

0.71 

108.01 

314 

190.9 

20.00 

20.00 

40.00 

2.10 

130.00 

27.05 

0.68 

99V57 

414 

173.4 

18.50 

18.50 

37.00 

2.13 

116.00 

26.26 

0.71 

86.99 

Average 

202.6 

21.50 

21.50 

43.00 

2.12 

136.50 

29.30 

0.69 

107.05 

Fourth  Test  Period.     January  27  to  February  5,   1915.     Ten  days.     Barley  and 

ground  corn  (1  to  1) 


114 
214 
314 
414 

247.6 
207.4 
195.6 
177.1 

26.00 
21.50 
20.00 
18.50 

26.00 
21.50 
20.00 
18.50 

52.00 
43.00 
40.00 
37.00 

2.10 
2.07 
2.04 
2.09 

164.00 
136.00 
130.00 
116.00 

31.96 

28.77 
26.22 
26.94 

0.62 
0.67 
0.66 
0.73 

132.65 

108.45 
100.16 
87.68 

Average 

206.9 

21.50 

21.50 

43.00 

2.07 

136.50 

28.47 

0.67 

107.23 

Fifth  Test  Period.    March  6  to  15,  1915.    Ten  days.     Ground  corn 

114 

214 
314 
414 

280.9 
230.9 
218.1 
201.1 

60.00 
48.60 
47.60 
43.80 

60.00 
48.60 
47.60 
43.80 

2.14 
2.10 
2.18 
2.18 

194.00 
158.00 
156.00 
142.00 

20.47 
17.38 
17.16 
17.45 

0.34 
0.36 
0.36 
0.40 

170.82 
139.98 
135.55 
118.51 

Average 

232.7 

50.00 

50:00 

2.15 

162.50 

18.11 

0.33 

141.21 

1917]  DIGESTIBILITY  OF  MIXED  'FEEDS;    INDIVIDUALITY  OF  PIGS 

TABLE  11. — Concluded 


Feeds  consumed 

Per 

Feces 

Pig 

Live 
weight 

Tank- 
age 

Ground 
corn 

Total 

day 
per 
100 
Ibs. 

Water 

Total 
feces 

per 
Ib.  of 
feed 

Total 
urine 

live 

weight 

Sixth  Test  Period.    March  16  to  25,  1915.    Ten  days.    Ground  corn 


114 

290.1 

60.00 

60.00 

2.07 

194.00 

21.35 

0.36 

172.29 

214 

239.1 



48.60 

48.60 

2.03 

158.00 

15.72 

0.32 

140.30 

314 

225.6 



47.60 

47.60 

2.11 

156,00 

16.69 

0.35 

132.43 

414 

207.6 



43.80 

43.80 

2.11 

142.00 

17.04 

0.39 

117.51 

Average 

240.6 

50.00 

50.00 

2.08 

162.50 

17.70 

0.37 

140.63 

Seventh  Test  Period.    April  22  to  May  1,  1915.     Ten  days.     Tankage  and  ground 

corn  (1  to  7.5) 


114 

352.6 

8.54 

64.06 

72.60 

2.06 

220.00 

30.84 

0.42 

173.22 

214 

286.9 

6.87 

51.53 

58.40 

2.04 

182.00 

21.43 

0.37 

139.52 

314 

275.6 

6.70 

50.30 

57.00 

2.07 

178.00 

22,97 

0.40 

130.58 

414 

256.1 

6.35 

47.65 

54.00 

2.11 

172.00 

21.40 

0.40  ' 

133.61 

Average 

292.8 

7.11 

53.38 

60.50 

2.07 

188.00 

24.16 

0.40 

144.23 

Eighth  Test  Period.     May  2  to  11,  1915.    Ten  days.     Tankage  and  ground  corn 

(1  to  7.5) 


114 

366.4 

8.54 

64.06 

72.60 

1.98 

220.00 

30.47 

0.42 

173.22 

214 

300.6 

6.87 

51.53 

58.40 

1.94 

182.00 

21.76 

0.37 

153.09 

314 

288.4 

6.70 

50.30 

57.00 

1.98 

178.00 

26.07 

0.46 

146.16 

414 

267.4 

6.35 

47.65 

54.00 

2.02 

172.00 

23.71 

0.44 

141.06 

Average 

305.7 

7.11 

53.38 

60.50 

1.98 

188.00 

25.50 

0.42 

153.38 

digestibility  of  the  dry  substance  of  the  rations  for  the  several  periods 
were  as  follows :  Periods  1  and  2,  in  which  ground  barley  alone  was 
fed,  70.8 ;  Periods  3  and  4,  in  which  ground  barley  and  ground  corn 
in  the  ratio  of  1  to  1  were  fed,  80.9 ;  Periods  7  and  8,  in  which  tank- 
age and  ground  corn  in  the  ratio  of  1  to  7.5  were  fed,  85.3 ;  and 
Periods  5  and  6,  in  which  ground  corn  alone  was  fed,  86.2. 

COEFFICIENTS  OF  DIGESTIBILITY  OF  THE  NUTRIENTS  OF  THE  RATIONS 

The  coefficients  of  digestibility  of  the  nutrients  of  the  rations  for 
the  four  pigs,  as  determined  directly,  for  the  eight  experimental 
periods  of  this  series  of  experiments  are  given  in  Tables  13  and  14. 

Ground  Barley. — It  is  evident  from  Table  13  that  the  coefficients 
of  digestibility  of  the  nutrients  for  ground  barley,  when  fed  alone  in 
Periods  1  and  2,  varied  for  the  different  animals  during  the  same  ex- 
perimental period.  This  is  especially  true  of  the  coefficients  for  the 
crude  fiber  and  the  ether  extract.  It  is  also  evident  that  the  coeffi- 
cients varied  considerably  for  the  same  animal  in  different  periods. 


76 


BULLETIN  No.  200 


[May, 


TABLE  12. — CHEMICAL  COMPOSITION  OF  THE  FECES 
(Results  expressed  in  percent  of  fresh  substance) 


Pig 

Dry 

substance 

Nitrogen- 
free 
extract 

Crude 
fiber 

Crude 
protein 

Ether 
extract 

Crude 
ash 

Total 
nitrogen 

First  Test  Period.    November  27  to  December  6,  1914.    Ten  days.    Barley 

114 
214 
314 
414 

27.86 
27.86 
29.13 
26.81 

14.03 
13.43 
13.94 
11.79 

3.67 
3.66 
3.59 

3.88 

6.77 
6.69 
7.58 
7.13 

0.95 
1.82 
1.79 
1.83 

2.45 
2.26 
2.24 
2.18 

1.083 
1.070 
1.213 
1.141 

Average 

27.92 

13.30 

3.70 

7.04 

1.60 

2.28 

1.127 

Second  Test  Period.    December  7  to  16,  1914.    Ten  days.    Barley 

114 
214 
314 
414 

25.25 
28.30 
29.34 

27.82 

10.94 
13.69 
14.01 
13.49 

3.88 
3.85 
3.65 
3.08 

7.08 
6.63 
7.66 
7.14 

0.89 
1.90 
1.81 
1.99 

2.46 
2.24 
2.21 
2.12 

1.132 

1.060 
1.222 
1.143 

Average 

27.68 

13.03 

3.62 

7.13 

1.65 

2.26 

1.139 

Third  Test  Period.    January  17  to  26,  1915.    Ten  days.    Barley  and  ground  corn 

(1  to  1) 


114 
214 
314 
414 

24.97 
24.16 
24.95 
23.15 

11.97 
11.52 
10.86 
10.21 

4.41 
4.48 
5.12 
4.34 

4.82 
4.85 
5.15 
5.29 

0.88 
0.99 
1.47 
1.13 

2.45 
2.31 
2.35 
2.18 

0.771 
0.776 
0.824 
0.846 

Average 

24.30 

11.14 

4.59 

5.03 

1.12 

2.32 

0.804 

Fourth  Test  Period.     January  27  to  February  5,  1915.    Ten  days.     Barley  and 
ground  corn  (1  to  1) 

114 
214 
314 
414 

25.80 
25.86 
27.02 
24.80 

11.93 
12.34 
12.68 
11.18 

4.67 
4.31 
4.25 
4.41 

5.10 
5.37 
5.47 
5.22 

1.66 
1.22 
2.25 
1.79 

2.44 
2.61 
2.37 
2.19 

0.816 
0.859 
0.875 
0.835 

Average 

25.87 

12.03 

4.41 

5.29 

1.73 

2.40 

0.846 

Fifth  Test  Period.    March  6  to  15,  1915.    Ten  days.    Ground  corn 

114 
214 
314 
414 

31.59 
31.94 
33.27 
31.10 

16.26 
16.76 
16.65 
15.35 

3.62 
3.41 
3.52 
3.49 

6.77 
6.49 
6.86 
6.23 

2.15 
2.62 
3.71 
3.52 

2.79 
2.66 
2.56 
2.52 

1.083 
1.012 
1.098 
0.997 

Average 

31.98 

16.26 

3.51 

6.59 

3.00 

2.63 

1.048 

Sixth  Test  Period.    March  16  to  25,  1915.    Ten  days.     Ground  corn 

114 
214 
314 
414 

32.64 
32.04 
33.66 
31.80 

16.03 
16.90 
16.26 
15.32 

3.58 
3.50 
3.52 
3.44 

6.99 
6.38 
7.01 
6.31 

3.33 
2.54 
4.12 
4.16 

2.72 
2.72 
2.75 
2.56 

1.118 
1.020 
1.121 
1.010 

Average 

32.54 

16.13 

3.51 

6.67 

3.54 

2.69 

1.067 

1917} 


DIGESTIBILITY  OF  MIXED  FEEDS;    INDIVIDUALITY  OF  PIGS 


77 


TABLE  12. — Concluded 


Pig 

Dry 

substance 

Nitrogen- 
free 
extract 

Crude 
fiber 

Crude 
protein 

Ether 
extract 

Crude 
ash 

Total 
nitrogen 

Seventh  Test  Period. 


April  22  to  May  1,  1915.     Ten  days.    Tankage  and  ground 
corn  (1  to  7.5) 


114 

32.39 

13.24 

3.20 

9.78 

1.73 

4.42 

1.565 

214 

30.28 

12.17 

2.93 

9.80 

1.81 

3.58 

1.568 

314 

31.67 

13.33 

3.24 

9.23 

2.13 

3.74 

1.476 

414 

32.85 

14.26 

3.27 

9.76 

1.45 

4.11 

1.561 

Average 

31.80 

13.25 

3.16 

9.64 

1.78 

3.96 

1.543 

Eighth  Test  Period.     May  2  to  11,  1915.     Ten  days.     Tankage  and  ground  corn 

(1  to  7.5) 


114 

27.90 

10.03 

3.10 

9.28 

1.19 

4.31 

1.484 

214 

29.87 

12.14 

2.85 

9.68 

1.19 

4:02 

1.548 

314 

32.14 

14.18 

3.15 

9.12 

1.78 

3.93 

1.459 

414 

32.40 

14.09 

3.30 

9.27 

1.82 

3.89 

1.483 

Average 

30.58 

12.61 

3.10 

9.34 

1.50 

4.04 

1.494 

The  average  coefficients  of  digestibility  of  the  nutrients  of  ground 
barley  when  fed  alone  to  the  four  pigs  for  the  two  ten-day  periods 
(eight  digestion  trials)  were  as  follows :  dry  substance,  70.8 ;  nitrogen- 
free  extract,  81.2 ;  crude  fiber,  14.1 ;  crude  protein,  54.0 ;  and  ether 
extract,  33.0.  Ground  barley  was  the  least  digestible  of  any  of  the 
rations  used  in  this  experiment.  The  coefficients  of  digestibility  of 
the  crude  protein,  the  ether  extract,  and  the  crude  fiber  were  very  low. 

Ground  Corn. — The  coefficients  of  digestibility  of  the  nutrients  of 
ground  corn  fed  alone  in  Periods  5  and  6  varied  somewhat  for  the 
different  pigs  during  the  same  period.  The  average  coefficients  of 
digestibility  of  all  the  nutrients,  except  those  of  the  ether  extract, 
agreed  very  closely  for  the  two  periods. 

The  average  coefficients  of  digestibility  of  the  nutrients  of  the 
ground  corn  when  fed  alone  to  each  of  the  four  pigs  for  the  two  ten- 
day  periods  (eight  digestion  trials)  were  as  follows:  dry  substance, 
86.2;  nitrogen-free  extract,  91.5;  crude  fiber,  38.8;  crude  protein, 
74.0 ;  and  ether  extract,  64.9.  These  results  for  the  dry  substance,  the 
<;rude  protein,  and  the  nitrogen-free  extract  agree  closely  with  the  cor- 
responding average  results  obtained  in  the  eight  digestion  experiments 
with  corn  reported  in  the  first  series  of  experiments. 

On  comparing  the  average  coefficients  of  the  nutrients  of  the  ration 
of  ground  corn  fed  alone  with  the  corresponding  averages  for  the 
ration  of  ground  barley  fed  alone,  it  will  be  noted  that  all  of  the 
nutrients  of  the  ground  corn  were  digested  much  more  thoroly  than 
those  of  the  ground  barley  alone. 

Ground  Barley  and  Ground  Corn  (1  to  1). — The  coefficients  of 
•digestibility  of  the  nutrients  of  the  ration  of  ground  barley  and  ground 


78 


BULLETIN  No.  200 


[May, 


TABLE  13. — COEFFICIENTS  OF  DIGESTIBILITY 


Pig 

Dry 
substance 

Nitrogen- 
free 
extract 

Crude 
fiber 

Crude 
protein 

Ether 
extract 

First  Test  Period.    November  27  to  December  6,  1914.    Ten  Days.    Barley 

114 
214 
314 
414 

Average 

73.5 
71.9 
69.8 
71.3 

71.6 

81.9 
81.1 
80.4 
82.9 

81.6 

20.9 
14.0 
15.5 
5.91 

16.8 

60.4 
57.4 
51.6 
53.0 

55.6 

64.9 

27.2 
28.2 
24.1 

36.1 

Second  Test  Period.    December  7  to  16,  1914.    Ten  days.    Barley 

114 
214 
314 
414 

Average 

74.2 
70.0 
67.7 
67.6 

69.9 

84.8 
80.3 
79.1 
78.7 

80.7 

10.1 
7.5 
9.2 
18.7 

11.4 

55.5 
56.8 
48.2 
48.8 

52.3 

64.6 
22.1 
22.8 
10.2 

29.9 

Third  Test  Period.    January  17  to  26,  1915.    Ten  days.    Barley  and  ground  corn 
(1  to  1) 

114 

214 
314 
414 

,     Average 

82.1 
80.8 
81.0 
81.0 

81.2 

88.9 
88.4 
89.5 
89.6 

89.1 

18.8 
10.0 
1.4* 
12.3 

13.7 

70.1 
67.1 
66.5 
63.9 

66.9 

80.6 
76.2 
66.2 

72.7 

73.9 

Fourth  Test  Period.     January  27  to  February  5,  1915.     Ten  days.     Barley  and 
ground  corn  (1  to  1) 

114 
214 
314 
414 

Average 

82.1 
80.5 
80.0 
79.6 

80.6 

89.5 
88.2 
88.1 
88.4 

88.6 

18.2 
17.8 
20.6 
8.5 

16.3 

69.9 
65.5 
65.5 
63.5 

66.1 

65.3 
72.1 
49.8 
59.5 

61.7 

Fifth  Test  Period.    March  6  to  15,  1915.    Ten  days.    Ground  corn 

114 
214 
314 
414 

Average 

87.2 
86.4 
85.7 
85.2 

86.1 

91.9 
91.2 
91.2 
91.0 

91.3 

40.1 
40.9 
38.4 
32.6 

38.0 

74.8 
74.6 
73.0 
72.9 

73.8 

78.3 
72.3 
60.3 
58.4 

67.3 

Sixth  Test  Period.    March  16  to  25,  1915.    Ten  days.    Ground  corn 

114 
214 
314 
414 

Average 

86.2 
87.7 
85.4 
85.3 

86.2 

91.6 
92.0 
91.6 
91.3 

91.6 

38.2 
45.0 
40.0 
35.0 

39.6 

72.8 
77.5 
73.2 
73.2 

74.2 

64.9 
75.6 
57.2 
52.0 

62.4 

'Not  included  in  the  average. 


1917] 


DIGESTIBILITY  OF  MIXED  FEEDS;    INDIVIDUALITY  OP  PIGS 


79 


TABLE  13. — Concluded 


Pig 

Dry 

substance 

Nitrogen- 
free 
extract 

Crude 
fiber 

Crude 
protein 

Ether 
extract 

Seventh  Test  Period.     April  22  to  May  1,  1915.     Ten  days.     Tankage  and  ground 

corn  (1  to  7.5) 


114 

84.1 

91.3 

48.6 

72.5 

73.5 

214 

87.2 

93.1 

59.4 

76.2 

76.2 

314 

85.2 

91.7 

50.7 

75.4 

69.2 

414 

85.2 

91.2 

51.1 

74.4 

79.3 

Average 

85.4 

91.8 

52.5 

74.6 

74.6 

Eighth  Test  Period.     May  2  to  11,  1915.     Ten  days.     Tankage  and  ground  corn 

(1  to  7.5) 


114 

86.5 

93.5 

50.9 

74.2 

82.0 

214 

87.1 

93.0 

60.0 

76.1 

84.0 

314 

83.0 

89.9 

45.7 

72.4 

70.7 

414 

83.6 

90.4 

45.3 

73.0 

71.2 

Average 

85.1 

91.7 

50.5 

73.9 

77.0 

TABLE  14. — SUMMARY  OF  THE  AVERAGE  COEFFICIENTS  OF  DIGESTIBILITY  OF 

THE  EATIONS 


Period 

Dry 
sub- 
stance 

Nitro- 
gen-free 
extract 

Crude 
fiber 

Crude 
protein 

Ether 
extract 

Ground  barley  

1 

716 

81  6 

16  8 

55  6 

36  1 

Ground  barley  

2 

699 

80.7 

11.4 

523 

29  9 

Average  

70.8 

81.2 

14.1 

540 

33  0 

Ground  barley  and  ground  corn 

3 

81.2 

89.1 

13.7 

66.9 

73.9 

Ground  barley  and  ground  corn 

4 

80.6 

88.6 

16.3 

66.1 

61.7 

Average  

80.9 

88.9 

15.0 

665 

678 

Ground  corn     

5 

86  1 

91.3 

38.0 

73  8 

67  3 

Ground  corn     

6 

86.2 

91.6 

39.6 

74  2 

62  4 

Average     

86  2 

91.5 

38.8 

74  0 

64  9 

Tankage  and  ground  corn  

7 

85.4 

91.8 

52.5 

74.6 

74.6 

Tankage  and  ground  corn  

8 

85.1 

91.7 

50.5 

73  9 

77  0 

Average.  . 

85.3 

91.8 

51.5 

74.3 

75.8 

corn  fed  together  in  the  ratio  of  1  to  1  in  Periods  3  and  4  varied  for 
the  different  animals  during  the  same  period.  This  is  especially  true 
of  the  coefficients  for  the  crude  fiber,  the  ether  extract,  and  the  crude 
protein.  The  average  coefficients  of  digestibility  of  the  nutrients  of 
this  ration  except  the  ether  extract  and  the  crude  fiber  agreed  very 
closely  for  the  two  periods. 

The  average  coefficients  of  digestibility  of  the  nutrients  of  the 
ration  of  ground  barley  and  ground  corn  fed  together  in  the  ratio  of 
1  to  1  to  each  of  the  four  pigs  for  the  two  ten-day  periods  (eight  diges- 


80  BULLETIN  No.  200  [May, 

tion  trials)  were  as  follows:  dry  substance,  80.9;  nitrogen-free  ex- 
tract, 88.9 ;  crude  fiber,  15.0 ;  crude  protein,  66.5 ;  and  ether  extract, 
67.8.  On  comparing  the  average  coefficients  of  the  nutrients  of  the 
ration  of  ground  barley  and  ground  corn  fed  together  in  the  ratio  of 
1  to  1  with  those  of  the  rations  of  ground  barley  and  of  ground  corn 
when  fed  alone,  it  will  be  noted  that  the  coefficients  of  the  nutrients  for 
the  ration  of  barley  and  corn  were  in  all  cases,  excepting  those  of  the 
ether  extract,  intermediate  between  those  of  the  barley  fed  alone  and 
those  of  the  corn  fed  alone. 

Tankage  and  Ground  Corn  (1  to  7.5). — The  coefficients  of  digesti- 
bility of  the  nutrients  of  this  ration  varied  significantly  for  the  differ- 
ent pigs  during  the  same  period.  The  average  coefficients  of  all  the 
nutrients  of  this  ration  agreed  closely  for  the  two  experimental  pe- 
riods. 

The  average  coefficients  of  digestibility  of  the  nutrients  of  the 
ration  of  tankage  and  ground  corn  fed  together  in  the  ratio  of  1  to  7.5 
to  each  of  the  four  pigs  for  the  two  ten-day  periods  (eight  digestion 
trials)  were  as  follows :  dry  substance,  85.3  ;  nitrogen-free  extract,  91.8 ; 
crude  fiber,  51.5 ;  crude  protein,  74.3 ;  and  ether  extract,  75.8.  These 
results  agree  quite  closely  with  the  corresponding  average  results  ob- 
tained in  the  eight  digestion  experiments  with  the  same  ration  reported 
above  in  the  first  series  of  experiments. 

On  comparing  the  average  coefficients  of  the  nutrients  of  this  ration 
with  those  of  the  ration  of  ground  barley  when  fed  alone,  it  will  be 
noted  that  all  of  the  nutrients  of  the  tankage  and  ground  corn  were 
digested  much  more  thoroly  than  those  of  the  barley. 

A  comparison  of  the  average  coefficients  of  the  nutrients  of  the 
ration  of  tankage  and  ground  corn  fed  together  with  the  ration  of  corn 
fed  alone  shows  that  the  dry  substance,  the  crude  protein,  and  the  nitro- 
gen-free extract  of  the  tankage  and  corn  were  digested  to  practically 
the  same  extent  as  those  of  the  ground  corn  alone,  while  the  ether  ex- 
tract and  the  crude  fiber  of  the  tankage  and  corn  were  digested  much 
more  thoroly  than  those  of  the  ground  corn  alone.  These  findings  are 
in  accord  with  those  obtained  in  the  first  series  of  experiments. 

THE  INFLUENCE   OF   ONE  FEED   UPON   THE   DIGESTIBILITY   OF   THE 
NUTRIENTS  OF  ANOTHER  FEED 

The  data  for  the  coefficients  of  digestibility  of  the  nutrients  of* 
barley,  as  determined  directly  when  fed  alone,  and  as  calculated  indi- 
rectly from  the  results  of  direct  digestion  experiments  with  the  com- 
bined ration  composed  of  barley  and  ground  corn  and  the  ground  corn 
alone,  are  given  in  Table  15.  It  will  be  noted  that  the  individual  data 
and  the  average  data  for  the  four  pigs  show  that  the  calculated  values 
indirectly  determined  for  the  coefficients  of  digestibility  of  the  dry 
substance,  the  nitrogen-free  extract,  the  crude  protein,  and  the  ether 


1917} 


DIGESTIBILITY  OF  MIXED  FEEDS;    INDIVIDUALITY  OF  PIGS 


81 


TABLE  15. — COEFFICIENTS  OF  DIGESTIBILITY  OF  GROUND  BARLEY,  DIRECTLY  AND 
INDIRECTLY  DETERMINED 


Pig 

Dry 

substance 

Nitrogen- 
free 
extract 

Crude 
fiber 

Crude 
protein 

Ether 
extract 

Ground  barley  fed  alone.    First  Test  Period 


114 

73.5 

81.9 

20.9 

60.4 

64.9 

214 

71.9 

81.1 

14.0 

57.4 

27.2 

314 

69.8 

80.4 

15.5 

51.6 

28.2 

414 

71.3 

82.9 

5.9 

53.0 

24.1 

Average 

71.6 

81.6 

16.8 

55.6 

36.1 

Ground  barley  calculated  from  the  barley  and  corn  ration.    Third  and  Fifth  Periods 


114 

77.3 

86.0 

10.0 

66.1 

84.5 

214 

75.5 

85.6 

-2.9 

60.8 

83.0 

314 

76.5 

87.8 

-13.9 

61.0 

76.4 

414 

77.9 

88.3 

3.9 

56.3 

76.0 

Average 

76.8 

86.9 

-0.7 

61.1 

80.0 

Ground  barley  fed  alone.    Second  Test  Period 


114 

74.2 

84.8 

10.1 

55.5 

64.6 

214 

70.0 

80.3 

7.5 

56.8 

22.1 

314 

67.7 

79.1 

9.2 

48.2 

22.8 

414 

67.6 

78.7 

18.7 

48.8 

10.2 

Average 

69.9 

80.7 

11.4 

52.3 

29.9 

Ground  barley  calculated  from  corn  and  barley  ration.    Fourth  and  Sixth 

Test  Periods 


114 

78.3 

87.4 

9.9 

67.4 

66.0 

214 

73.7 

84.4 

6.5 

55.3 

66.1 

314 

74.9 

84.6 

12.6 

59.1 

37.0 

414 

74.3 

85.4 

-2.6 

55.3 

61.8 

Average 

75.3.  . 

85.5 

6.6 

59.3 

57.7 

extract  of  the  barley  are  considerably  higher  than  the  corresponding 
coefficients  of  the  barley  determined  directly  by  the  digestion  experi- 
ments. 

While  the  calculated  results  for  the  crude  fiber  are  irregular,  they 
nevertheless  indicate  that  the  calculated  coefficients  indirectly  deter- 
mined for  this  nutrient  of  the  barley  are,  on  the  whole,  somewhat  lower 
than  the  corresponding  coefficients  of  the  barley  determined  directly. 

The  data  for  the  coefficients  of  digestibility  of  the  nutrients  of  the 
ground  corn,  as  determined  directly  when  fed  alone,  and  as  calculated 
indirectly  from  the  direct  experiments  with  the  ration  composed  of 
barley  and  ground  corn  and  the  barley  alone,  are  given  in  Table  16.  A 
study  of  these  data  leads,  in  general,  to  the  same  conclusions  as  to  the 
variations  and  differences  between  the  direct  and  indirect  coefficients 
of  the  nutrients  of  ground  corn  as  were  found  in  the  case  of  the  direct 
and  indirect  coefficients  for  barley. 


82 


BULLETIN  No.  200 


[May, 


The  data  for  the  coefficients  of  digestibility  of  the  nutrients  of  the 
ration  composed  of  one  part  of  ground  barley  and  one  part  of  ground 
corn,  as  determined  directly  and  as  calculated  indirectly,  first,  from 
the  direct  determinations  for  the  barley  and  the  corn  rations,  and 
second,  from  the  indirect  determinations  for  the  barley  and  the  corn 
rations  are  given  in  Table  17.  It  is  apparent  that  the  coefficients  for 
the  dry  substance,  the  nitrogen-free  extract,  the  crude  protein,  and 
the  ether  extract  of  the  ration  calculated  from  the  coefficients  for  the 
ground  barley  and  the  ground  corn,  each  determined  directly,  are 
considerably  lower,  while  those  for  the  crude  fiber  are  considerably 
higher,  than  the  corresponding  coefficients  directly  determined  for  the 
mixed  ration.  These  findings  seem  to  prove  that  the  dry  substance, 


TABLE  16. — COEFFICIENTS  OF  DIGESTIBILITY  OF  GROUND  CORN,  DIRECTLY  AND 
INDIRECTLY  DETERMINED 


Pig 

Dry 
substance 

Nitrogen- 
free 
extract 

Crude 
fiber 

Crude 
protein 

Ether 
extract 

Ground  corn  fed  alone.    Fifth  Test  Period 

114 

87.2 

91.9 

40.1 

74.8 

78.3 

214 

86.4 

91.2 

40.9 

74.6 

72.3 

314 

85.7 

91.2 

38.4 

73.0 

60.3 

414 

85.2 

91.0 

32.6 

72.9 

58.4 

Average 

86.1 

91.3 

38.0 

73.8 

67.3 

Ground  corn  calculated  from  the  barley  and  corn  ration.    First  and  Third 

Test  Periods 


114 

91.2 

96.0 

13.9 

81.6 

89.5 

214 

90.2 

95.7 

•0.2 

78.7 

58.2- 

314 

92.8 

98.6 

-32.5 

84.2 

88.0 

414 

92.2 

96.4 

30.5 

76.9 

56.4 

Average 

91.6 

96.7 

3.0 

80.4 

73.0 

Ground  corn  fed  alone.     Sixth  Test  Period 


114 

86.2 

91.6 

38.2 

72.8 

64.9 

214 

87.7 

92.0 

45.0 

77.5 

75.6 

314 

85.4 

91.6 

40.0 

73.2 

57.2 

414 

85.3 

91.3 

35.0 

73.2 

52.0 

Average 

86.2 

91.6 

39.6 

74.2 

62.4 

Ground  corn  calculated  from  the  barley  and  corn  ration.     Second  and  Fourth 

Test  Periods 


114 

90.5 

94.3 

37.7 

86.9 

65.7 

214 

91.6 

96.1 

42.5 

75.7 

44.7 

314      • 

93.0 

97.2 

48.3 

86.1 

65.4 

414 

92.4 

98.0 

-16.2 

80.9 

81.6 

Average 

91.9 

96.4 

28.1 

82.4 

64.4 

1917} 


DIGESTIBILITY  OF  MIXED  FEEDS;    INDIVIDUALITY  OF  PIGS 


83 


TABLE  17. — COEFFICIENTS  OF  DIGESTIBILITY  OF  A  EATION  OF  GROUND  BARLEY  AND 
GROUND  CORN  (1  TO  1),  DIRECTLY  AND  INDIRECTLY  DETERMINED 


Pig 

Dry 

substance 

Nitrogen- 
free 
extract 

Crude 
fiber 

Crude 
protein 

Ether 
extract 

Ground  barley  and  ground  corn  (1  to  1)  fed  together,  direct  determination. 
Third  Test  Period 

114 
214 
314 
414 

Average 

82.1 
80.8 
81.0 
81.0 

81.2 

88.9 
88.4 
89.5 
89.6 

89.1 

18.8 
10.0 
1.4 
12.3 

13.7 

70.1 
67.1 
66.5 
63.9 

66.9 

80.6 
76.2 
66.2 
72.7 

73.9 

Ground  barley  and  ground  corn  (1  to  1)  calculated  from  the  direct  determinations 
of  the  barley  ration  and  the  corn  ration.     First  and  Fifth  Test  Periods 

114 
214 
314 
414 

Average 

80.2 
79.0 
77.5 
78.1 

78.7 

86.9 
86.1 
85.8 
86.9 

86.4 

26.5 
21.9 
22.2 
13.7 

21.1 

67.0 
65.3 
61.4 
62.1 

64.0 

73.4 
55.9 
48.6 
45.9 

56.0 

Ground  barley  and  ground  corn   (1  to  1)   calculated  from  the  indirect  determina- 
tions for  the  barley  ration  and  the  corn  ration   (see  second  sections 
of  Tables  15  and  16) 

114 
214 
314 
414 

Average 

87.1 
82.7 
84.4 
84.9 

84.0 

91.0 
90.6 
93.2 
92.3 

91.8 

11.1 
-2.0 
-19.3 
11.0 

0.2 

73.2 
69.0 
71.6 
65.7 

69.9 

87.7 
91.0 
83.8 
98.7 

90.3 

Ground  barley  and  ground  corn  (1  to  1)   fed  together,  direct  determination. 
Fourth  Test  Period 

114 
214 
314 
414 

Average 

82.1 
80.5 
80.0 
79.6 

80.6 

89.5 

88.2 
88.1 
88.4 

88.6 

18.2 
17.8 
20.6 
8.5 

16.3 

69.9 
65.5 
65.5 
63.5 

66.1 

65.3 
72.1 
49.8 
59.5 

61.7 

Ground  barley  and  ground  corn  (1  to  1)  calculated  from  the  direct  determinations 
of  the  barley  ration  and  the  corn  ration.     Second  and  Sixth  Test  Periods 

114 
214 
314 
414 

Average 

80.0 
78.6 
76.3 
76.2 

77.8 

88.2 
86.1 
85.3 
85.0 

86.2 

18.3 
18.5 
18.2 
23.5 

19.6 

63.4 
66.3 
59.6 
60.0 

62.3 

64.8 
56.1 
44.7 
42.1 

51.9 

Ground  barley  and  ground  corn  (1  to  1)  calculated  from  the  indirect  determination 
of  the  barley  ration  and  the  corn  ration  (see  fourth  sections  of  Tables  15  and  16) 

114 
214 
314 
414 

Average 

84.2 
82.4 
83.8 
83.1 

83.4 

90.8 
90.2 
90.9 
91.1 

90.8 

18.0 
17.0 
23.1 
-6.5 

12.9 

76.3 
64.7 
71.4 
67.0 

69.9 

65.8 
87.1 
55.0 
76.6 

71.1 

84  BULLETIN  No.  200  [May, 

the  nitrogen-free  extract,  the  crude  protein,  and  the  ether  extract  of 
the  two  feeds  when  fed  together  are  more  digestible  than  they  are  when 
fed  alone,  while  the  crude  fiber  is  less  digestible.  On  the  other  hand, 
it  is  evident  from  the  data  given  in  Table  17  that  the  coefficients  for 
the  dry  substance,  the  nitrogen-free  extract,  the  crude  protein,  and  the 
ether  extract  of  the  ration  calculated  from  the  coefficients  determined 
indirectly  for  the  barley  and  the  ground  corn  rations  are  considerably 
higher,  while  those  of  the  crude  fiber  are  considerably  lower,  than  the 
corresponding  coefficients  directly  determined  for  the  mixed  ration. 

It  should  be  noted  in  this  connection  that  the  coefficients  for  the 
dry  substance  and  the  nitrogen-free  extract  for  the  wheat  flour  mid- 
dlings and  the  ground  corn  ration,  calculated  from  the  direct  deter- 
minations of  the  middlings  and  the  ground  corn  fed  singly  (see  page 
69),  were  considerably  higher  than  those  directly  determined  from 
the  mixed  ration.  However,  the  coefficients  for  the  dry  substance 
and  the  nitrogen-free  extract  for  the  barley  and  ground  corn  ration, 
calculated  from  the  direct  determinations  of  the  barley  and  ground 
corn  fed  singly  (see  page  83),  were  considerably  lower  than  those 
directly  determined  from  the  mixed  ration.  Further,  the  co- 
efficients for  the  protein  of  the  wheat  flour  middlings  and  the  ground 
corn  ration,  calculated  from  the  direct  determinations  of  the  mid- 
dlings and  the  ground  corn  fed  singly,  were  not  much  different  from 
those  directly  determined  for  the  mixed  ration.  However  the  coeffi- 
cients for  the  protein  of  the  barley  and  ground  corn  ration,  calculated 
from  the  direct  determinations  of  the  barley  and  corn  fed  singly,  were 
considerably  lower  than  those  directly  determined  from  the  mixed 
ration. 

It  is  therefore  evident  that,  in  some  cases,  one  feed  does  not  influ- 
ence the  digestibility  of  the  individual  nutrients  of  another  feed  and, 
in  other  cases,  it  does  influence  the  digestibility  of  the  individual  nutri- 
ents of  the  other  feed  in  one  of  the  two  following  ways:  first,  the 
nutrients  of  the  feeds  when  fed  as  mixed  feeds  are  more  digestible 
than  they  are  when  each  feed  is  used  alone ;  or,  second,  the  nutrients  of 
feeds  when  fed  as  mixed  feeds  are  less  digestible  than  they  are  when 
each  feed  is  used  alone.  "With  the  limited  data  at  present  available 
relating  to  this  subject,  it  is  impossible  to  explain  logically  the  above 
mentioned  differences  shown  by  different  combinations  of  feeds  upon 
the  digestibility  of  their  nutrients  as  compared  with  the  digestibility 
of  the  nutrients  of  the  individual  feeds  when  fed  alone.  This  subject 
is  being  further  studied  at  this  station. 

The  results  of  these  researches  on  the  influence  of  one  feed  upon 
the  digestibility  of  another  feed  demonstrate  clearly,  first,  that  the  co- 
efficients of  digestibility  of  feeds  calculated  indirectly  by  subtracting 
the  weights  of  the  digestible  nutrients  of  one  feed  as  directly  deter- 
mined in  other  periods  from  the  corresponding  values  for  two  feeds 


1917]  DIGESTIBILITY  OF  MIXED  FEEDS;    INDIVIDUALITY  OF  PIGS  85 

combined  may  be,  and  probably  often  are,  decidedly  inaccurate ;  and 
second,  that  the  weights  of  the  digestible  nutrients  of  a  mixed  ration 
calculated  by  the  use  of  the  coefficients  of  digestibility  of  the  nutrients 
obtained  directly  for  the  individual  feeds  when  fed  alone  may  be  de- 
cidedly inaccurate. 

It  therefore  seems  evident  from  these  considerations  that,  in  order 
to  obtain  accurate  results  for  the  coefficients  of  digestibility  of  mixed 
rations,  digestion  experiments  should  be  made  directly  upon  the  mixed 
rations  as  fed.  In  other  words,  in  the  future,  coefficients  of  digesti- 
bility of  the  nutrients  for  mixed  rations  should  be  obtained  and  re- 
ported, rather  than  merely  those  for  the  individual  feeds  composing 
the  rations. 

INDIVIDUALITY  OF  PIGS  AS  TO  THE  THORONESS  WITH  WHICH  THEY 

DIGEST  THEIR  FEED 

The  data  for  the  coefficients  of  digestibility  of  the  crude  protein 
obtained  in  thirty- two  digestion  trials  of  ten  days  each,  in  which  four 
rations  were  fed  to  each  of  four  pigs,  are  given  in  Table  18.  Examina- 
tion of  the  figures  shows  that  the  individual  coefficients  for  Pig  214 
are  significantly  greater  than  the  individual  coefficients  for  Pig  414, 
in  each  of  the  eight  experiments.  A  similar  comparison  of  the  coeffi- 
cients of  digestibility  of  protein  for  Pigs  214  and  314  demonstrates 
a  similar  significant  difference.  Since  conditions  thruout  the  experi- 
ment were  practically  identical,  the  pigs  also  being  litter  mates  and 
having  been  fed  together  from  birth,  the  data  lead  clearly  to  the  con- 
clusion that  the  distinct  and  well-defined  differences  between  the  co- 
efficients of  digestibility  of  crude  protein  for  Pig  214  and  Pigs  314  and 
414  thruout  the  eight  experiments  must  have  been  due  to  individuality. 
A  further  study  of  the  data  of  this  table  shows  that  there  is  a  con- 
siderable difference  between  the  coefficients  of  digestibility  of  crude 
protein  for  Pigs  114  and  314  and  for  Pigs  114  and  414  that  apparently 
can  be  assigned  to  the  factor  of  individuality.  However,  there  are 
practically  no  differences  in  the  coefficients  of  digestibility  of  crude 
protein  for  Pigs  114  and  214,  or  for  Pigs  314  and  414,  that  can  be 
assigned  to  the  factor  of  individuality. 

Examination  of  the  results  presented  in  Table  18  for  the  coeffi- 
cients of  digestibility  of  the  ether  extract  of  the  four  rations  shows  that 
there  were  marked  and  well-defined  differences  due  apparently  to  the 
individuality  of  the  pigs. 

Inspection  of  the  data  given  in  Table  18  for  the  coefficients  of  the 
dry  matter  and  the  nitrogen-free  extract,  shows  that  there  was  a 
tendency  toward  individual  differences  especially  in  the  average  results. 
However,  the  individuality  of  these  pigs  with  reference  to  their  power 
of  digesting  dry  matter  and  nitrogen-free  extract  is  not  so  clearly 
evident  as  it  is  in  the  case  of  crude  protein  and  ether  extract. 


86 


BULLETIN  No.  200 


[May, 


TABLE  18. — SUMMARY  OF  THE  COEFFICIENTS  OF  DIGESTIBILITY  OF  THE  NUTRIENTS 

SHOWING  THE  INDIVIDUALITY  OF  PIGS  AS  TO  THE  THORONESS  WITH 

WHICH  THEY  DIGESTED  THEIR  FEED 


Period 

Eation 

Pig 

214 

Pig 

114 

Pig 

314 

Pig 
414 

Pig 
214 

Pig 
114 

Pig 
314 

Pig 
414 

Crude  protein 

Ether  extract 

1 
2 
3 

4 
5 
6 

7 
8 

Barley  (alone)  .  .  . 
Barley  (alone)  .  .  . 
Barley  and  corn 
(Itol).  . 

57.4 
56.8 

67.1 
65.5 
74.6 
77.5 
76.2 

76.1 
68.9 

60.4 
55.5 

70.1 
69.9 

74.8 
72.8 
72.5 

74.2 
68.8 

51.6 

48.2 

66.5 
65.5 
73.0 
73.2 
75.4 

72.4 
65.7 

53.0 
48.8 

63.9 
63.5 
72.9 
73.2 
74.4 

73.0 
65.3 

64.9 
64.6 

80.6 
65.3 
78.3 
64.9 
73.5 

82.0 
71.8 

27.2 
22.1 

76.2 
72.1 
72.3 
75.6 
76.2 

84.0 
63.2 

24.1 
10.2 

72.7 
59.5 
58.4 
52.0 
79.3 

71.2 
53.4 

28.2 
22.8 

66.2 
49.8 
60.3 

57.2 
69.2 

70.7 
53.1 

Barley  and  corn 
(Ito  1)  

Ground  corn 
(alone)  

Ground  corn 
(alone)  

Tankage  and  corn 
(Ito  7.5)  

Tankage  and  corn 
(Ito  7.5)  

Averasre.  . 

Dry  substance 


Nitrogen-free  extract 


1 

2 
3 

Barley  (alone)  .  .  . 
Barley  (alone)  .  .  . 
Barley  and  corn 
(Ito  1).  . 

73.5 
74.2 

1 
82.1 

71.9 
70.0 

80.8 

71.3 
67.6 

81.0 

69.8 
67.7 

81.0 

81.9 

84.8 

889 

81.1 
80.3 

884 

82.9 
78.7 

89  6 

80.4 
79.1 

895 

4 

Barley  and  corn 
(Itol).  . 

82.1 

80.5 

79.6 

80.0 

89  5 

88  2 

884 

88.1 

5 

Ground  corn 
(alone)  

87.2 

86.4 

85.2 

85.7 

91.9 

91.2 

91.0 

91  2 

6 

Ground  corn 
(alone)  , 

86  2 

87.7 

85  3 

85  4 

91  6 

92  0 

91  3 

91  6 

7 

Tankage  and  corn 
(Ito  7.5)  

84.1 

87.2 

85.2 

'85.2 

91.3 

93.1 

91.2 

91.7 

8 

Tankage  and  corn 
(Ito  7.5)  

865 

87.1 

83  6 

83  0 

93  5 

93  0 

904 

899 

Averaere.  . 

81.9 

81.5 

79.9 

79.5 

89.2 

88.4 

87.9 

87.7 

The  results  of  this  second  series  of  experiments  show  greater  dif- 
ferences in  the  coefficients  of  digestibility  of  the  nutrients  of  the  same 
feeds  by  different  animals  than  did  those  of  the  first  series.  For  ex- 
ample, the  average  coefficient  of  digestibility  of  the  protein  in  the  eight 
tests  for  Pig  214  was  5.5  percent  greater  than  that  for  Pig  414.  Again, 
the  average  coefficient  of  digestibility  of  the  ether  extract  in  the  eight 
tests  for  Pig  114  was  35.2  percent  greater  than  that  for  Pig  414.  The 
total  gain  in  live  weight  of  Pig  114  for  the  80  days  was  26.3  percent 
greater  than  that  for  Pig  414. 

The  results  of  this  second  series  of  experiments  support  those  ob- 
tained in  the  first  series  of  experiments  in  demonstrating  that  the  co- 
efficients of  digestibility  of  the  nutrients  of  a  number  of  different  ra- 
tions show  constantly  higher  values  for  some  pigs  than  for  others. 

The  total  gains  in  weight  of  each  of  the  four  pigs  used  in  this 
experiment  during  the  eight  experimental  periods,  each  of  ten  days' 


1917]  DIGESTIBILITY  OF  MIXED  FEEDS;    INDIVIDUALITY  OF  PIGS  87 

duration  during  which  time  each  of  the  four  animals  received  the 
same  kind  of  feeds  and  approximately  the  same  quantity  of  feeds  per 
100  pounds  of  live  weight,  were  as  follows:  Pig  114,  62.5  pounds;  Pig 
214,  57.0  pounds;  Pig  314,  54.5  pounds;  and  Pig  414,  49.5  pounds.  The 
average  live  weights  of  the  pigs  during  the  eight  experimental  periods 
were  as  follows :  Pig  114,  277.5  pounds ;  Pig  214,  229.8  pounds ;  Pig  314, 
218.3  pounds;  and  Pig  414,  200.5  pounds.  The  weights  of  the  total 
feeds  consumed  during  this  same  time  were  as  follows :  Pig  114,  459.2 
pounds ;  Pig  214,  376.8  pounds ;  Pig  314,  364.0  pounds ;  and  Pig  414, 
335.6  pounds.  The  weights  of  feed  required  to  produce  100  pounds  of 
gain  during  the  ten  experimental  periods  were  as  follows :  Pig  114, 
735  pounds;  Pig  214,  661  pounds;  Pig  314,  668  pounds;  and  Pig  414, 
678  pounds. 

Comparing  these  gains  in  live  weight  and  the  economy  of  gains  in 
weight  with  the  average  coefficients  of  digestibility  of  the  nutrients  of 
the  feeds  for  each  animal,  it  will  be  observed  that  there  is  possibly  a 
better  correlation  between  the  coefficients  of  digestibility  and  the  gains 
or  the  economy  of  the  gains  in  weight  in  this  second  series  of  experi- 
ments than  there  was  in  the  first  series.  For  example  Pig  214,  which 
on  the  average  digested  all  of  the  nutrients  of  the  feeds  somewhat  more 
thoroly  than  Pigs  314  and  414,  altho  weighing  on  an  average  277.5 
pounds,  made  a  gain  of  57  pounds  and  required  only  661  pounds  of 
feed  to  produce  100  pounds  of  gain ;  while  Pigs  314  and  414,  weighing 
only  218.3  and  200.5  pounds,  respectively,  made  gains  of  54.5  and 
49.5  pounds,  respectively,  and  required  668  and  678  pounds  of  feed, 
respectively,  to  produce  100  pounds  of  gain.  These  results  would  seem 
to  indicate  that  Pig  214  possibly  made  more  economical  gains  than  Pigs 
314  and  414.  Further,  Pig  314,  which  on  the  average  digested  all  of 
the  nutrients  of  the  feeds  only  very  slightly  more  thoroly  than  Pig 
414,  altho  weighing  somewhat  more  than  that  pig,  yet  possibly  made 
slightly  the  more  economical  gains  of  the  two.  On  the  other  hand,  Pig 
114,  which  on  the  average  digested  all  of  the  nutrients  of  the  feeds 
almost  as  thoroly  as  Pig  214,  altho  weighing  47.7  pounds  more  than 
Pig  214,  gained  62.5  pounds  but  required  735  pounds  of  feed  to  pro- 
duce 100  pounds  of  gain,  while  Pig  214  gained  57  pounds  and  required 
only  661  pounds  of  feed  to  produce  100  pounds  of  gain.  However, 
the  difference  between  these  two  pigs  as  to  economy  of  gains  may  be 
due,  in  large  part  at  least,  to  the  difference  in  their  live  weights. 


88 


BULLETIN  No.  200 


[May.. 


SUMMARY  OF  DATA  OF  BOTH  SERIES  OF  EXPERIMENTS 

1.  Dry  Substance. — The  order  of  the  rations  according  to  decreas- 
ing coefficients  of  digestibility  of  their  dry  substance  was  as  follows: 
ground  corn,  87.1 ;  tankage  and  ground  corn,  86.0 ;  ground  barley  and 
ground  corn,  80.9;  wheat  flour   middlings    and   ground   corn,   79.1; 
wheat  flour  middlings,  74.4 ;  and  ground  barley,  70.8. 

2.  Nitrogen-free  Extract. — The  order  of  the  rations  according  to 
decreasing  coefficients  of  digestibility  of  their  nitrogen-free  extract 
was  as  follows:    tankage  and  ground  corn,  92.2;  ground  corn,  92.1; 
ground  barley  and  ground  corn,  88.9;    wheat   flour   middlings   and 
ground  corn,  85.9;  wheat  flour  middlings,  81.2;  and  ground  barley, 
81.2. 

3.  Crude  Fiber. — The  order  of  the  rations  according  to  decreasing 
coefficients  of  digestibility  of  their  crude  fiber  was  as  follows:  tankage 
and  ground  corn,  51.2 ;  ground  corn,  34.8 ;  wheat  flour  middlings,  21.0 ; 
ground  barley  and  ground  corn,  15.0 ;  ground  barley,  14.1 ;  and  wheat 
flour  middlings  and  ground  corn,  12.1. 

4.  Crude  Protein. — The  order  of  the  rations  according  to  decreas- 
ing coefficients  of  digestibility  of  their  crude  protein  was  as  follows: 
wheat  flour  middlings,  80.0 ;  wheat  flour  middlings  and  ground  corn, 
77.3 ;  tankage  and  ground  corn,  74.8.;  ground  corn,  74.5 ;  ground  bar- 
ley and  ground  corn,  66.5 ;  and  ground  barley,  54.0. 

5.  Ether  Extract. — The  order  of  the  rations  according  to  decreas- 
ing coefficients  of  digestibility  of  the  ether  extract  was  as  follows: 
wheat  flour  middlings,  85.4 ;  wheat  flour  middlings  and  ground  corn, 
83.4 ;  tankage  and  ground  corn,  80.8 ;  ground  corn,  68.3 ;  ground  bar- 
ley and  ground  corn,  67.8;  and  ground  barley,  33.0. 

6.  Average  Coefficients  of  Digestibility  of  the  Rations. — The  fol- 
lowing is  a  summary  of  the  average  coefficients  of  the  rations  fed  in 
these  experiments : 


Ration 

No. 
of 
ex- 
peri- 
ments 

Dry 

sub- 
stance 

Nitro- 
gen- 
free 
ex- 
tract 

Crude 
fiber 

Crude 
pro- 
tein 

Ether 
ex- 
tract 

Wheat  flour  middlings  

16 

74.4 

81.2 

21.0 

80.0 

85.4 

16 

87.1 

92.1 

34.8 

74.5 

68.3 

Ground  barley  

8 

70.8 

81.2 

14.1 

54.0 

33.0 

Wheat  flour  middlings  and  ground  corn 
(1  to  1)  .  . 

8 

79.1 

85.9 

12.1 

77.3 

83.4 

Ground  barley  and  ground  corn  (1  to  1) 
Tankage  and  ground  corn  (1  to  7.5)  .... 

8 
16 

80.9 
86.0 

88.9 
92.2 

15.0 
51.2 

66.5 

74.8 

67.8 
80.8 

1917] 


DIGESTIBILITY  OF  MIXED  FEEDS;    INDIVIDUALITY  OF  PIGS 


89 


7.  Influence  of  One  Feed  upon  the  Digestibility  of  the  Nutrients 
of  Another  Feed. — The  following  is  a  summary  of  the  average  results 
which  show  the  influence  of  one  feed  upon  the  digestibility  of  another 
feed: 


Ration 

No. 
of 
ex- 
peri- 
ments 

Dry 
sub- 
stance 

Nitro- 
gen- 
free 
ex- 
tract 

Crude 
fiber 

Crude 
pro- 
tein 

Ether 
ex- 
tract 

Middlings  —  direct  

8 

74.7 

82.2 

22.8 

79.3 

82.3 

Middlings  —  indirect  

8 

70.7 

77.2 

6.1 

78.3 

89.3 

Corn  —  direct  

8 

87.8 

92.7 

30.8 

75.1 

71.7 

Corn  —  indirect  

8 

83.7 

88.9 

-2.2 

73.0 

81.3 

Barley  —  direct  

8 

70  8 

81.2 

14.1 

540 

33.0 

Barley  —  indirect  

8 

76  1 

862 

3.7 

60.2 

68.9 

Corn  —  direct  

8 

862 

91.5 

38.8 

74.0 

o4.9 

Corn  —  indirect  

8 

91.8 

96.6 

15.6 

81.4 

68.7 

Middlings  and  corn  —  direct  

8 

79.1 

86.0 

12.1 

77.3 

83.5 

Middlings  and  corn  —  indirect1  

8 

81.1 

88.1 

24.8 

78.0 

78.8 

Middlings  and  corn  —  indirect2  

8 

77.1 

83.8 

-0.7 

76.6 

88.1 

Barley  and  corn  —  direct  

8 

80.9 

88.9 

15.0 

66.5 

67.8 

Barley  and  corn  —  indirect1  

8 

78.3 

86.3 

20.4 

63.2 

54.0 

Barley  and  corn  —  indirect2.  . 

8 

83.7 

91.3 

6.6 

69.9 

80.7 

'Calculated  from  the  direct  determinations  of  the  coefficients  of  the  individual 
feeds. 

'Calculated  from  the  indirect  determinations  of  the  coefficients  of  the  individual 
feeds. 

8.  Individuality  of  Pigs  as  to  the  Thoroness  With  Which  They 
Digest  Their  Feeds. — Summaries  of  the  nutrients  of  the  feeds  showing 
the  individuality  of  pigs  as  to  the  thoroness  with  which  they  digest  their 
feeds  are  given  on  pages  72  and  87  of  this  bulletin. 


CONCLUSIONS 

1.  The  weights  of  the  feces  of  pigs,  per  pound  of  feed,,  vary  mark- 
edly depending  upon  the  character  of  the  ration.    Such  differences  in 
the  weights  of  the  feces  per  pound  of  feed  are  due,  in  large  part  at 
least-,  to  variations  in  the  water  content  of  the  feces  and  to  variations 
in  the  coefficients  of  digestibility  of  the  dry  substance  of  the  rations. 

2.  The  results  obtained  in  these  experiments  clearly  indicate  that 
in  some  cases  one  feed  does  not  influence  the  digestibility  of  the  indi- 
vidual nutrients  of  another  feed  with  which  it  is  fed,  and  in  other 
cases  that  it  does  influence  the  digestibility  of  the  individual  nutrients 
of  the  other  feed  in  one  of  the  two  following  ways :  first,  the  nutrients 
of  the  feeds  when  fed  as  mixed  feeds  are  more  digestible  than  they  are 
when  each  feed  is  used  alone;  or,  second,  the  nutrients  of  the  feeds 
when  fed  as  mixed  feeds  are  less  digestible  than  they  are  when  each 
feed  is  used  alone.    With  the  limited  data  at  present  available  relating 


90  BULLETIN  No.  200  [May, 

to  this  subject,  it  is  impossible  to  explain  logically  these  differences 
shown  by  different  combinations  of  feeds,  when  fed  together,  upon  the 
digestibility  of  their  combined  nutrients  as  compared  with  the  digesti- 
bility of  the  nutrients  of  the  individual  feeds  when  fed  alone. 

3.  The  results  of  these  researches  on  the  influence  of  one  feed 
upon  the  digestibility  of  another  feed  demonstrate  clearly :  first,  that 
the  coefficients  of  digestibility  of  the  nutrients  of  feeds  calculated  indi- 
rectly by  subtracting  the  weights  of  the  digestible  nutrients  of  one  feed 
as  directly  determined  in  other  tests  from  the  corresponding  values  for 
the  two  feeds  combined,  may  be,  and  probably  often  are,  decidedly 
inaccurate ;  and  second,  that  the  weights  of  the  digestible  nutrients  of 
a  mixed  ration,  calculated  by  the  use  of  the  coefficients  of  digestibility 
of  the  nutrients  obtained  directly  for  the  individual  feeds  when  fed 
alone,  may  be  decidedly  inaccurate. 

4.  It  therefore  apparently  follows  that  in  order  to  obtain  strictly 
accurate  results  for  the  coefficients  of  digestibility  of  mixed  rations, 
digestion  experiments  should  be  made  directly  upon  the  mixed  rations 
as  fed.    In  other  words,  in  the  future  coefficients  of  apparent  digesti- 
bility of  the  nutrients  for  mixed  rations  should  be  obtained  and  re- 
ported, rather  than  those  for  individual  feeds  composing  the  rations. 

5.  The  results  of  these  experiments  demonstrate  clearly  that  dif- 
ferent animals  of  the  same  species  may  show  individuality  as  to  the 
thoroness  with  which  they  digest  the  nutrients  of  their  feeds.    In  other 
words,  under  conditions  that  are  practically  identical  thruout  the  same 
experiment,  the  coefficients  of  digestibility  of  the  nutrients  of  a  num- 
ber of  different  rations  show  significantly  higher  values  for  some  pigs 
than  for  others.    However,  the  differences  in  the  coefficients  of  digesti- 
bility of  the  nutrients  of  the  same  feeds  by  the  different  pigs  are  prob- 
ably too  small  to  be  considered  of  much,  if  any,  practical  or  economic 
importance. 


The  authors  wish  to  acknowledge  the  efficient  assistance  rendered 
by  W.  F.  Campbell  in  the  feeding,  weighing,  and  care  of  the  animals. 


1917} 


DIGESTIBILITY  OF  MIXED  FEEDS  ;    INDIVIDUALITY  OP  PIGS 


91 


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BULLETIN  No.  200 


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1917] 


DIGESTIBILITY  OF  MIXED  FEEDS;    INDIVIDUALITY  OF  PIGS 


94 


BULLETIN  No.   200 


UNIVERSITY  OF  ILLINOIS-URBANA 


